Neuroscience Unit III

What is insulin?

Released into bloodstream by beta cells of the pancreas; it is a vitally important hormone that allows glucose in the blood to be taken up by cells, tightly regulating amount of glucose in blood. INSULIN is not needed for glucose to be transported into neurons (always possible)

What is the monoamine hypothesis?

Researchers developed hypothesis that mood is closely tied to the levels of released monoamine neurotransmitters, NE or 5-HT in the brain. depression is a consequence of a deficit in one of these diffuse modulatory systems. Lower levels of monoamines could cause depression, while introducing higher than normal levels is an effective treatment for depression

What happens to a sensory system when it loses input?

Researchers found that the neighboring areas of the cortex take over the UNUSED SPACE; the neighboring parts take over the space in the cortex

What is the nucleus accumbens do in terms of drugs?

Responsible for translating motivation into action. MOTIVATION. COMPULSION (HABITS) PERSEVERATION: continuing to do something over and over again; almost OCD. Located between motivational area and movement area.

How does retrieval work?

Retrieval is taking memories that are long-term and returning them to active working memory; you do not think about long-term memories directly, but rater CALL THEM UP and get them in another representation in consciousness so you can be consciously aware of them.

What is MCH?

MCH is a peptide neurotransmitter found in the lateral hypothalamus; MCH-neurons have a direct connection to the leptin-sensitive arcuate neurons, and also project throughout most of the cerebral cortex, telling cortex the leptin levels in blood, and potentially playing large role in food seeking behavior

What are Bowerbirds?

Male Bowerbirds each built a very particular kind of Bower (home for family); the bower complexity correlates with the size of the cerebellum; hugely dimorphic behavior correlates with some measure of brain size (among the same sex in this case)

What are the neural implications of genotype?

Males get X-linked diseases because they only have one X-chromosome, so one defect on the X-chromosome is automatically displayed (females have a backup; must have defect in both X to display it).

What did the study regarding MARMOSET Fathers yield?

Marmoset fathers help take care of the young. Found that fatherhood increases level of dendritic spines and vasopressin V1a receptors in your brain in the primate prefrontal cortex (site of executive decision making)

What are anxiolytic medications?

Medications that reduce anxiety; they act by altering chemical synaptic transmission in the brain. Include Benzodiazepines and SSRIs

What is declarative memory?

Memory for facts, events, and places. largely ephemeral; but memory capacity is ENORMOUS (limitless?); storage for declarative memory especially involves the hippocampus and cortex

Where does memory reside, as indicated by the novel to familiar stimulus experiment?

Memory resides in patterns of activity across neurons. In neural networks, when a specific face is displayed, one neuron has the MSOT response, while the other have smaller response; it is this SPECIFIC DISTRIBUTION OF ACTIVITY across these range of neurons that is the unique distribution of that face, and therefore the NEURAL ACTIVITY OF THAT FACE.

Where does memory reside?

Memory resides in the distributed pattern of activity across neurons; it resides in the comparison/ratio of activity between cells. Faces and objects therefore are not solely represented in one neuron or cell, but rather represented in the unique distribution they occupy across cells. Allows you to remember things even if a neuron dies, because that neuron doesnt hold a memory ALONE

What is SHORT TERM MEMORY?

Memory with LARGE CAPACITY; duration is HOURS to DAYS, and involves hippocampus. It is NOT permanent, but is long-lasting so there does seem to be a neural change involved. It is not distrupted by distraction, but can be disrupted by head trauma.

What experiment was done with MICE concerning the potential clinical use of reconsolidation?

Mice had foot shock paired with sound. HDAC2 protein found a while after this; neuroplasticity genes off. Turned neuroplasticity genes ON by inhibiting HDAC2; made sound without foot shock; no longer paired sound with shock; memory is malleable. . potentially could erase bad memories.

What generated LTD in an experiment?

Stimulated two inputs in alteration; then give train of lower frequency stimulation. Discovered that long train of LOW-frequency stimulation applied to input 1 would cause a depression of synaptic transmission in input 1 alone (With no change for input 2); HOMOSYNAPTIC LTD

What happened when they induced STRABISMUS in the animal in terms of the histogram of ocular dominance groups and the percentage of neurons that are monocular, equally binocular, or favoring-one-eye binocular?

Strabismus is the misalignment of the eye; the neurons are getting dissimilar inputs from eyes; incongruous feeds; neurons in binocular layers basically choose ONE EYE or the OTHER to respond to; dramatic decrease in binocular neurons (neurons responding to BOTH eyes); changed the experience and received change on the level of response in neurons

How is cortisol made?

Stress triggers hypothalamic parvocellular neurons to release CRH into the anterior pituitary, which releases ACTH into the general circulation, which binds to the adrenal cortex, stimulating the production of Cortisol, which will return back and negatively inhibit the production of more CRH by binding to hypothalamic neurons.

What kind of memory is the striatum involved in?

Striatum includes the basal ganglia and putamen and evidence supports the involvement of the striatum in inhabit learning and procedural memory

How does calcium flux through NMDA receptors modify synaptic transmission to make it stronger?

Strong NMDA receptor activation triggers modification of AMPA receptors. Ca enters and activates protein kinases; one substrate is AMPA receptors; phosphorylating AMPA causes it to increase its conductance, and to deliver new AMPA receptors to the post-synaptic membrane (yielding stronger synaptic transmission). Delivery of AMPA receptors is also correlated with STRUCTURAL changes in the synapse; namely DENDRITIC SPINES

What does the spatial experiment suggest about the hippocampus?

Suggests that WORKING MEMORY might also be a part of hippocampal function. Without a hippocampus, the animals have difficulty using recent experiences to influence behavior, particularly for tasks that require spatial navigation.

What is a partial complex seizure?

Symptoms are variable depending on what brain area is effected; but AURA often proceeds seizure. May have a sense of deja vu proceeding seizures or visual hallucinations. It has a more gradual start and stop. MOST COMMON location for these is in temporal lobes; often yields bizarre dream/memory like experience; people lose touch with surroundings; seem in a daze. MORE of a SLOW increase in brain activity that picks up.

What does "neurons that fire together wire together" mean?

Synapses are validated based on their ability to participate in the firing of their postsynaptic partner. The key appears to be CORRELATION: a single synapse has little influence on the postsynaptic neuron; to be heard, the activity of the synapse must be correlated with the activity of many other inputs converging on the same postsynaptic neuron.

What is synaptic rearrangement?

Synaptic rearrangement occurs as a consequence of neural activity and synaptic transmission.

What sexual dimorphisms exist that explain Zebra Finch singing?

Syrinx (vocal cords) in birds is controlled by VCR (vocal control region) in the brain. Male VCRs are 5X the size of female VCRs. Have organizational effects of androgens; VCRs develop and become large if bird is going to be male. Also have activational effects as hormones LATER in life generate the ability of the animal to sing its song.

What are hedonic attributes?

TASTE and SMELL of the food. They are more predictive mechanisms that will influence feeding behavior to a certain degree, but is ultimately subordinate to other signals. Taste and smell activate positive reward circuitry, stimulating EATING + increasing probability of behavior.

What if we put TTX in the eye instead of closing the eyelid?

TTX prevents any action potentials from firing at all by blocking Na-channels. No input at all from one eye fails to yield ocular dominance shift.

What experiment was done with the TMS machine involving blind people?

Tested to see what errors when reading braille for blind person v. seeing person when different parts of the brain were disrupted. When occipital cortex was disrupted, blind people had difficultly reading braille, while when the somatosensory cortex was disrupted, non-blind people had difficultly reading braille.

What is the HPA axis?

The hypothalamic-pituitary-adrenal cortex. A complex set of direct influences and feedback interactions among three glands; it is an important mediator of the stress response

What controls the anterior lobe of the pituitary?

The hypothalamus itself is the true master gland of the endocrine system. The anterior lobe is under the control of neurons int he periventricular area called PARVOCELLULAR neurosecretory cells

What is the VTA?

Ventral Tegmental Area. Where dopaminergic neurons in the dopaminergic diffuse modulatory synapse are situated. MAJOR dopamine output to nucleus accumens and prefrontal cortex

What is the motivational circuit?

Ventrotegmental area (where the dopaminergic neurons reside); these neurons project to the nucleus accumbens and the prefrontal cortex. These three areas are all interconnected, and this circuit is critical for craving and drug seeking behavior.

What role do vital organs play in causing organisms to drink?

Vital organs, namely the brain, heart, and kidney are involved in the homeostatic regulation of blood volume; vital organs MUST be adequately perfused with blood at ALL TIMES

What are the stages if addiction?

1. Acute Drug Effects 2. Transition to Addiction: involves transcriptional regulators, protein expression changes. 3. Addiction: REWIRING of circuits in the brain; there are enduring changes; your brain on drugs is NOT the same as your brain without drugs

What are treatments for anxiety disorders?

1. Benzodiazepines (immediate) 2. SSRIs (delayed) 3. Psychotherapy (delayed) 80% respond to treatment for anxiety disorders. high success rate.

What was the activity found in the two cells of the prefrontal cortex in delayed response task?

1. CELL 1: response linked to visual input (and potentially the salience of what was going on); response of neuron increased during CUE and CHOICE periods. 2. CELL 2: during the cue period, the response starts to build, and during the delay period, the response continues to go UP and UP and stays high during this period, and as soon as the animal makes a choice, the neurons response drops; appear to resemble working memory; memory held onto via electrical activation and then discarded when information is no longer necessary.

Who is Robert Schumann, and why is he important?

A composer with bipolar disorder. During periods of severe depression, he produced NO MUSIC, but during periods of hypomania, he produced a LARGE body of work; mood correlated to a large degree with what he did

How does the hypothalamic regulation of temperature happen?

A regulated parameter, like temperature, is measured by specialized sensory neurons. deviations from the optimal range are detected by neurons concentrated in the periventricular zone of the hypothalamus (where a SET POINT has been established), which then orchestrate an integrated response to bring the parameter back to its optimal value. the hypothalamus sets the set point in the preoptic nuclei

What is the mesocorticolimbic dopamine system?

A subdivision of the dopaminergic system; dopaminergic projections arising from the ventral tegmental area project to the frontal cortex and parts of the limbic system. Evidence indicates that it is involved in the reward system, and reinforces certain adaptive behaviors (especially projects to nucleus accumbens)

Who is DAVID REIMER?

Boy who was basically turned into a female; believed that maybe the way you raise a child determines behavior (gender completely man made). He was raised a girl; had surgery and estrogen injections. Seemed to KNOW he was a male; felt "wrong" his entire childhood and was always attracted to females

What is the NIH definition of addiction?

COMPULSIVE DRUG SEEKING and CONSUMPTION despite severe adverse consequences (social, personal, economic and health); lost ability to make choices that will promote well being. ADDICTION is a brain disease affected by the environment and genetics.

What is the sympathetic division like?

Chain of ganglia next to spinal cord (sympathetic ganglia); the preganglionic neurons in the CNS synapse onto the sympathetic ganglia lining the vertebrae column, and then the postganglionic cells are noradrenergic (make NE and release it into target tissue); tend to ACTIVATE target tissue

What is the effect of chronic stress on WOODCHUCKS?

Chronic Stress results in degeneration of hippocampal dendrites

What effect does chronic stress have on people?

Chronic stress will RESULT in CELL DEATH and reduced hippocampal size. This is a problem because impaired hippocampal function can result in improper regulation of the HPA axis; if the hippocampus cannot NEGATIVELY inhibit the HPA axis, there will be increased levels of cortisol, and increased stress

What are cognitive dimorphisms between the sexes?

Claim that girls tend to do better on verbal paths than boys. Claim that boys tend to be better on spatial navigation and 3D manipulation tasks. Cognitive dimorphisms are speculative and unimpressive, especially when individual variation is taken into account.

What happens mechanistically when you close one eye?

Closed eye yields weak NMDA receptor activation by poorly correlated activity; it triggers loss of AMPA receptors. There is spontaneous activity in retina when eye is closed, but there is NO PATTERN/ORDER; potential decoupling of neighboring neurons; NOT activating NMDA receptors but rather LOSING connections and decreasing the number of receptors on the post-synaptic side. NEURONS that FIRE TOGETHER WIRE TOGETHER, and NEURONS THAT FIRE OUT OF SYNC FAIL TO LINK. Body disconnects with noisy information because it isnt useful.

What characterizes non-REM sleep?

Composes 75% of sleep time; consists of 4 stages based on the shape of the frequencies of the EEG; there is SOME MUSCLE TONE and LITTLE MOVEMENT during this period punctuated by occasional dreams. ANS is dominated by PARASYMPATHETIC activity during this time. Larger Amplitude, Lower Frequency EEG (SLOW WAVE SLEEP)

What is HYPERPHAGIA?

Compulsive overeating. When the ventromedial hypothalamus was lesioned, the animals ate until they were obese. Researchers labeled the ventromedial hypothalamus as the Satiety Center

What is long-term memory?

Concept of ENGRAM (memory trace). it has a large (unlimited) capacity, and duration can extend from weeks to years to a lifetime, for it generates very STABLE physical changes in the brain. Even people with head trauma will generally remember their earlier life. Involves CEREBRAL CORTEX

How should we interpret human hippocampus recordings?

Continuum from sensory input to memory encoding; these cells arent essential for RECALL, BUT may be involved in memory formation for things that we already recognize; invovled in secondary process whereby the recognition is then associated with all the connotations for that person place or thing

What negative-feedback mechanisms exist within the stress response? What happens during chronic stress?

Cortisol can send a feedback signal to the hypothalamus to STOP releasing CRH, which shuts down this stress-mechanism. When there is chronic stress, the shut-off valve is circumvented

What were the effects of lesions in the prefrontal cortex for delayed response tasks?

Found that delayed response tasks were disrupted by prefrontal cortex lesions; if there is a lesion, animals performance is degraded.

What are NMDA receptors?

Glutamate-Gated Ion channels that allow the passage of cations such as calcium and sodium into the cell. In the absence of glutamate, the channels close.

Can learning occur after critical periods? Who is Mike May?

Mike May is a man who lost his vision when a child; he regained partial vision after a cornea transplant using stem cells. His vision didnt really come back because while his cornea was fixed, it didn't really wire up correctly to the cortex; he could recognize some objects, but he had poor facial recognition.

What are MAOs?

Monoamine oxidase is an enzyme that breaks down monoamines; monoamine oxidase inhibitors INHIBIT this breakdown process, and are often used for treatment of depression by boosting monoamine levels

What were the conclusions drawn from the vole experiment in mate selection? What differentiation exists between the sexes?

Monogamous voles have oxytocin and vasopressin receptors in the brain's reward areas. FEMALES: monogamous have lots of oxytocin binding receptors in nucleus accumbens MALES: monogamous have lots of vasopressin receptors in ventral pallidum

What do addictive drugs do in the short term?

Liking, not wanting category (use because they feel good). Intoxication is acute behavioral change. Addictive drugs are REINFORCING (rather than rewarding).

What is LTP?

Long term Potentiation *A consequence of strong NMDA receptor activation is a strengthening of synaptic transmission *One consequence of strong NMDA receptor activation and the resulting flood of calcium ions into the postsynaptic dendrite is the insertion of new AMPA receptors into the synaptic membrane; this makes transmission STRONGER

What is LTD?

Long-Term DEPRESSION; can store memories equally well by making synapses WEAKER. LTD is triggered by WEAK NMDA receptor activation. It is associated with dendritic spine SHRINKAGE.

What are mood disorders?

MAJOR depression and Bipolar disorders. Lifetime prevalence is 6-20%. It is somewhat more common in women than men (differences in hormones potentially contribute). 15% suicide rate in untreated depression. 1.5 to 3 times more common in first degree relatives, indicative of biological/genetic factors.

What is the MC4 receptor? What effect does it have on feeding?

MC4 receptor is a receptor in the lateral hypothalamus that alphaMSH and AgRP both bind to, eliciting opposite effects. AlphaMSH is the agonist, AgRP the antagonist; when activated, it serves to inhibit lateral hypothalamus and reduce feeding behavior.

What is the phenotype of mood disorders?

No response to surroundings but instead persists in a state of LOW MOOD with little ability to feel joy. Mood, sleep, appetite, and self esteem are all effected. Symptoms of depression must exist for 2+ weeks before major depression is diagnosed.

How does PCP inhibit the normal function of NMDA receptors?

Normally NMDA channels, in the presence of glutamate, allow the passage of both sodium and calcium when glutamate binds, yielding depolarization. NMDA channels are blocked when PCP enters and binds and the blocking of these receptors produces effects on behavior that resemble the symptoms of schizophrenia.

How does drinking water favor ISOTONICITY?

OVLT neurons located outside the blood-brain barrier serve as osmometers, which sense the osmolarity of the systemic circulation, and if blood is too thick, the OVLT neurons detect this, and signal release of vasopressin (ADH)

What is the difference between a reward v. a reinforcer?

Reward: a stimulus that the brain interprets as intrinsically POSITIVE (something to be approached: food, sex, warmth). Reinforcer: increases the probability of the behavior associated with it will be repeated. Substance abusers can reach point where they do NOT WANT to take the drug, but are COMPELLED to do so; reinforcement circuits have been emphasized in the brain; at this point reward is irrelevant.

How do you learn to recognize a face?

Start in visual cortex (V1), and from the striate cortex, information is distributed to the parietal and temporal lobe; the information goes through the VENTRAL STREAM, which is the brain stream important for object recognition. Neurons here are responding to increasingly complex and abstract stimuli. Area IT (the inferotemporal cortex) contains neurons that are specialized to detect images of faces, and show remarkable selectivity in that one neuron will respond vigorously to one face, and generate NO AP to another.

What happens to gray matter in SCHIZOPHRENIA?

Stereotypical loss of gray matter; gray matter loss is proportional to severity of symptoms. Default mode network structures are implicated: prefrontal cortex, parietal cortex, cingulate cortex; all play putative role in introspection and consciousness

What are GRID CELLS in ENTORHINAL CORTEX?

Provides INPUT to hippocampus. These cells respond to a whole grid-like pattern of spots; responses at spatial gridpoints potentially involved in navigation. The entorhinal cortex and nearby hippocampus are first things to go in Alzheimer's disease, and a main symptom of the disease is spatial disorientation (lack of ability to navigate)

What was the experiment involving Voles in mate selection?

Quantified vole behavior; had three chambers with male vole in middle, a partner chamber, and a stranger chamber. Monogamous prairie voles went to partner, while Montane voles visited both and spent time on their own as well.

What is fatal familial insomnia?

RARE disease that occurs around 50 years of age or so; people usually die in 1 to 3 years after first being diagnosed. Shows that with enough sleep deprivation, body suffers SO MUCH that the person will die. This kind of insomnia results in hallucinations, weight loss, degree of dementia, and NO EFFECT when given sleeping pills. Found to be a PRION DISEASE ala MAD COW that produces a lot of degeneration, especially in the thalamus (potentially messing up pacemakers).

What are the two major phases of sleep?

REM and Non-REM

How is hippocampus important for spatial navigation in rats?

Rat study done shows that hippocampus is involved in spatial memory. Had MAZE; when there were hippocampus lesions, rat was inefficient in finding food, while rats with a normal hippocampus retrieve the cheese efficiently (dont go down same radial arm twice).

What experiment did they do regarding the Dopaminergic System, and what were their findings?

Rats in skinner box who hit lever received shock to ventral tegmental area, causing feelings of pleasure. This results in rat becoming addicted to self-stimulation at the cost of its own health. Self stimulation of ventral tegmental area activates the nucleus accumbens and other reward pathways, forming the basis of addictive behaviors.

What is aphagia? Lesioning what area of the brain generates this?

Refusal to eat. When LATERAL HYPOTHALAMUS was lesioned, the animals starved themselves. Researchers labeled lateral hypothalamus as a potential feeding center

What does VASOPRESSIN DO?

Regulates blood volume and salt concentration. Vasopressin-containing neurons receive information about low blood volume and respond by releasing vasopressin, which acts directly on the kidneys and leads to water retention and reduced urine production

What are potential susceptibility genes related to Schizophrenia?

Related to: • Neuronal Transmission • MYELINATION • METABOLIC PATHWAYS

Who is patient H.M.?

patient had horrible epileptic seizures. Had large bilateral removal of tissue of medial temporal lobe. He had PROFOUND anterograde amnesia; incapable of remembering anything new for entire life. Normal NON-declarative memory (working and procedural); illustrate that they are different circuits. By taking out hippocampus, seem to have destroyed the consolidating portion of the brain; incapable of transferring information.

What is the preoptic nuclei?

the hypothamaus sets the set point for thermoregulation in the preoptic nuclei; the preoptic nuclei receives information regarding the temperature status of the blood via the carotid artery, and activates corresponding systems if the body is not within the correct temperature range

Does cocaine trigger LTP?

yes. One cocaine injection; 24 hours later prepare VTA slices; see LTP at VTA synapses. Change in AMPA and NMDA ratio

What do magnocellular neurons from the hypothalamus release?

*Magnocellular neurons of the PVZ (Periventricular Zone) of the hypothalamus release OXYTOCIN and VASOPRESSIN directly into the bloodstream via the POSTERIOR PITUITARY *Magnocellular axons terminate right on the capillary walls located in the posterior lobe of the pituitary, sending the hormones directly into bloodstream *These neurohormones regulate processes ranging from homeostasis (more vasopressin) to mother-infant attachment (oxytocin)

How does the temporal lobe factor into memory? Lateral parts of cortex? Medial parts of cortex?

*Temporal Lobe--Declarative memory formation + storage *Lateral Cortex: VISUAL AREAS (IT Area) that respond to complex objects and faces *MEDIAL Cortex: have hippocampus; memory + learning

What happened to the TT London taxi driver, and what does this suggest?

*A man with initials TT was a London taxi driver for 40 years and he subsequently suffered bilateral hippocampus damage from encephalitis *His navigation abilities were good when major routes were used, while his navigation abilities were POOR on side roads *Might this be a spatial memory deficit that is brought out when fine-grained spatial memory is required?

How is hypovolemia addressed in the body?

*Decreased blood volume causes vasopressin to be released in the posterior pituitary by magnocellular neurosecretory cells; vasopressin acts directly on the kidneys to increase water retention and inhibit urine production • Mechanoreceptors in the walls of major blood vessels and heart signal the loss of blood pressure that accompanies a loss of blood volume; these signals make their way to the hypothalamus via the vagus nerve and nucleus of the solitary tract • A rise in blood levels of angiotensin II occurs in response to reduced blood flow to the kidneys; circulating angiotensin II acts on neurons of the subfornical organ in the telencephalon, which stimulates the magnocellular neurosecretory cells of the hypothalamus to release vasopressin • Stimulation of sympathetic ANS to constrict arterioles

What role does exercise play in alleviating depression?

*Found to be JUST as effective as SSRI's in treating milder forms of depression if people exercise around 5 times a week; regular aerobic exercise has large effect *Exercise increases bloodflow into the brain; seems to promote cell growth in hippocampus

What may contribute to the slightly higher depression rates found among women as compared to men?

*GONAD HORMONES & STRESS *Increase in depression in women between puberty and menopause *Mood effects from hormonal supplements and oral contraception *Premenstrual mood effects *Postpartum depression

What did they find about genetic variation regarding vasopressin receptors in HUMANS?

*Genetic variation in vasopressin receptor 1a gene associates with pair bonding behavior in humans *Found that people who have this specific mutation (polymorphism) have problems with pair-bonding behavior; marital problems; tend to get divorced

What were the experiments concerning human working memory, specifically in regards to FACES and LOCATIONS? What parts of the brain lit up?

*Identity tasks: Prefrontal Cortex Activation *Location tasks: Dorsal Area Activation OVERLAP in activation for identity and location tasks in the CINGULATE CORTEX. This shows that different areas of the brain may be stimulated by the same sensory input if you are meant to examine a specific area of it; task-specific memory

How does hippocampus and its relationship to memory reveal itself in LONDON Taxi drivers?

*London taxi drivers must memorize thousands of streets; the size of their hippocampus correlates with experience; taxi drivers have larger hippocampus than age-matched non-drivers *Also evidence of their hippocampus being active while recalling a route (vs. passing viewing) *CANT be sure, but perhaps there are place cells and grid cells in the human brain

What effect do the Parvocellular neurons in the hypothalamus have on the body?

*The parvocellular neurons of the PVZ (periventricular zone) activate cells in the anterior lobe of the pituitary by releasing hypophysiotropic hormones *The axons of parvocellular neurons synapse into capillary beds in the local circulation of the anterior pituitary, releasing hypophysiotropic hormones; this causes stimulation or inhibition of anterior pituitary hormone release (the hormones from the hypothalamus activate cells in the anterior pituitary, causing them to release hormones into the circulatory system); the hormone is transported in the BLOOD, yielding action or organs of the body

How to people with prefrontal lesions perform on the WISCONSIN Card Sorting Task?

*They can learn to do it but they are SLOW to pick up the category *Difficulty changing behavior when sort rule changes

Could new Ca receptors be necessary for cocaine relapse? Do they still nose-poke for cocaine when Ca-permeable glutamate receptors in the NAc are blocked?

*To test this experimentally, they delivered NASPM into the nucleus accumbens of rats during cocaine withdrawal *NASPM (blocks AMPA activity) was delivered locally into the nucleus accumbens; NASPM-treated rats had dramatically lower levels of responding ➢ During withdrawal, there is an increase in Ca-permeable AMPA receptors in nucleus accumbens synapses; blocking these receptors interferes with reinstatement of cocaine-seeking behavior in vivo ➢ Cocaine promotes LTP in the nucleus accumbens

What experiment was done concerning wild baboons?

*Wild baboons are an excellent model to study the effects of chronic stress due to their highly structured social hierarchies *Baboons organize themselves into hierarchical societies; researchers started observing baboons and looking at socially dominant v. inferior *They found that subordinate baboons are chronically stressed and have HIGH basal cortisol levels; these baboons usually suffer from high-blood pressure, ulcers, and depression *FOUND to be a high correlation concerning the more socially accepted and dominant you are, the lower levels of stress you have

What is monocular deprivation and what does it shown about the striate cortex?

*if sealed shortly after birth, a striking result is that the OPEN-EYE columns expand in width, while the closed eye columns SHRINK This type of synaptic rearrangement is EXPERIENCE DEPENDENT because it relies on the *There is CRITICAL PERIOD during which this synaptic structural rearrangement may occur; at the end of the critical period, the LGN afferents LOSE their capacity for growth and retraction, and are CEMENTED IN PLACE

What are What are the two major groups of sex hormones for males and females?

1. ANDROGENS: sex hormones more concentrated in males; testosterone is the principal hormone (females only have 10% of testosterone males have) 2. ESTROGENS: sex hormones more concentrated in females; estradiol and progesterone are the principal hormones

What are some paradoxes concerning Ghrelin concentrations?

1. ANOREXIA Nervosa: people with anorexia had higher resting Ghrelin levels 2. Obese people had LOWER resting Ghrelin levels than lean people

What are the TWO response phases in response to decreased blood volume?

1. Cardiac Phase: sensors in heart and great vessels detect decreased blood pressure and signal NTS (Nucleus of the Solitary Tract), which signals the hypothalamus to activate the sympathetic nervous system. Sympathetic innervation causes heart to beat faster with greater force, the peripheral arterioles to constrict, and BP to rise. 2. Renal Phase: juxtaglomerular apparatus senses decreased BP, which causes release of RENIN; renin made into angiotensin II, which causes the hypothalamus to secrete ADH (Vasopressin), which acts on the kidney to conserve water. Angiotensin II is also a potent dipsogen (inducer of thirst)

What are some X-linked diseases that males get?

1. Color Blindness: mutation of one of the photopigments (usually for red or green), making it difficult to discriminate between some colors 2. Duchene Muscular Dystrophy: defective dystrophan gene involved in synapse function that yields profound muscular weakness (wheelchair bound; trouble breathing); potential CNS consequences include lower IQ, reduced # of neurons, EEG abnormalities, and abnormal dendritic spines; shows that gene effects can have a tremendous effect on the CNS

What differences do addictive drugs have?

1. Different behavior effects 2. Different molecular targets 3. Different abuse potentials

What are the FOUR patterns of communication in the nervous system?

1. Direct Synaptic Signaling 2. Diffuse Modulatory Systems 3. Neuroendocrine Signaling via the Hypothalamus 4. Networks of ANS

What are some main visual critical periods in terms of TYPE OF VISION?

1. Direction selectivity: can expose animal to certain DIRECTIONS disproportionately, yielding a bias in their neurons to that specific direction so they will respond more aggressively in that direction stimulus 2. ORIENTATION SELECTIVITY 3. OCULAR DOMINANCE PLASTICITY

Why do some people get addicted and others dont?

1. Dose of drug that reaches the brain + HOW FAST the drug gets to brain 2. GENETIC INFLUENCE: family influence on susceptibility to addiction; not determinant 3. DIFFERENT DRUGS have DIFFERENT ADDICTION POTENTIALS; may have to do with dose that reaches the brain 4. STRESS; increased stress yields increased addiction like behavior

What two categories of seizures exist?

1. GENERALIZED SEIZURES: Lose consciousness, and all of the brain is effected *Tonic Clonic Seizures (Grand Mal) *Absence Seizures (Petit Mal) 2. PARTIAL SEIZURES: portion of the brain is affected, often in one hemisphere; most common kind of seizure; often made man causes *Simple Partial Seizure *Complex Partial Seizure

What are the activational effects of estradiol?

1. Hypothalamus: if estradiol is applied, see tremendous growth of neurites 2. Hippocampus: estradiol correlates with the number of dendritic spines on neurons in the hippocampus; potentially enhanced spatial navigation during high levels of estradiol (like when pregnant); improved maze performance in rats that correlates with rodent fertility 3. Periodic variations in neural properties: will depolarize neurons by altering potassium conductance (increased excitability of neurons) and increased dendritic spines

Why do Critical periods end mechanistically?

1. Less Plasticity when Axonal Growth Ends. 2. Less Plasticity when Cortical Activation is constrained 3. Increased Inhibition in circuits as you get older and mature; plays HUGE role in defining critical periods 4. Less Plasticity when Synaptic Transmission Matures 5. Increased myelination and glial cell growth impedes change; lack of space for neurons + axon movement

What are critical periods for song birds?

1. Male Zebra Finch: has critical period for listening to song of a tutor bird; will start using his vocalizations to try to make song; during sensorimotor period he has to be able to use his motor apparatus to produce his OWN SONG (similar but not identical to tutor) 2. Canaries: have critical periods every season as they develop new songs each year 3. Sparrows: critical period where they have to hear song of male tutor; the sensorimotor period happens a few months later

What is the basal forebrain complex of the cholinergic system?

1. Medial Septal Nuclei Project to Hippocampus (important for learning and memory) 2. Basal Nuclei of Meynert projects to Neocortex *1+2 neurons are first to degenerate in Alzheimer's disease

What are some treatments for mood disorders?

1. Medications: tricyclics, MOAIs, SSRIs 2. Psychotherapy 3. Electroconvulsive Therapy (ECT)

What are three contributing factors to mood disorder?

1. Monoamine Synthesis; monoamines are involved in depression; synthesis, release, reuptake, breakdown 2. HPA axis 3. Gender: gonad hormones

What is the difference between place cells and grid cells?

1. Nearby cells have similar grid spacing and orientation, but different phases of LIGHT AND DARK. 2. Distant cells may have different spacing and orientation. 3. Mapping NOT same as hippocampus.

Where do brain rhythms come from?

1. Neural Pacemakers; The thalamic neurons project to thousands of cortical neurons in a synchornized manner; they are sensitive to chemicals from diffuse modulatory systems in the brain; to get coherent ++ synchronized action of brain, have a lot of neurons project to thalamus because pacemaker cells can help regulate. 2. Feedback Circuits; alternating phases of system being active and shut down; getting constant input that will excite, and then inhibiting neuron inhibits

What is the locus coeruleus and where is it located?

A cluster of neurons in the pons where the noradrenegic diffuse modulatory system arises from. Researchers have found that the noradrenergic system is most activated by new and unexpected non-painful stimuli; functions to increase brain responsiveness

What do we NEED for experience dependent cortical plasticity?

1. Neuromodulators 2. Specific + significant changes in neural firing patterns 3. Critical Periods: within neurodevelopmental time frame

What are hormonal organizational and activational effects?

1. Organizational effects: hormones setting up the system; generating male and female BRAIN & BODY development (before birth) 2. Activational effects: temporary changes in the circulating levels of hormones that have a transient effect on something

Overall, what are causes and factors contributing to Schizophrenia?

1. Overactive dopamine systems 2. Underactive Glutamate Systems 3. Possible protective role of estrogen; disease is less prevalent and less severe in women

What two different voles were studied in mate selection experiment?

1. Prairie Voles: tend to be monogamous 2. Montane Voles: non pair-bonding voles that continuously change mates

What is NARCOLEPSY?

1. REM SLEEP ATTACKS 2. CATAPLEXY: inappropriately timed atonia 3. SLEEP PARALYSIS: atonia persists after awake. 90% of the cases are caused by degeneration of hypocretin neurons that are in the lateral hypothalamus; this degradation is thought to be due to an autoimmune disease; it can be brought on BY STRESS AND EMOTION. People often given ritalin to stay awake.

What is the difference between simple and complex partial seizures?

1. SIMPLE: consciousness is NOT LOST but it is altered 2. COMPLEX: consciousness is LOST

What are human hippocampus recordings?

1. Some neurons are selective to OBJECT CATEGORIES 2. SOME cells show remarkable selectivity to specific things

What effects do drugs of abuse have over longer periods?

1. TOLERANCE: reduced response to drug upon repeated exposure. 2. DEPENDENCE: the NEED to continue drug exposure in order to avoid withdrawal symptoms 3. Triggering of associations: changes akin to learning and memory; happens in parts of brain involved in reinforcing.

Why do we drink?

1. To maintain normal concentrations of ions, proteins, etc inside and outside the cell 2. Vital organs are sensitive to blood perfusion rates, so must keep blood volume and blood pressure within specific range

What are some major antidepressants?

1. Tricyclic compounds: block the reuptake of NE and 5-HT by transporters 2. SSRIs 3. NE-selective reuptake inhibitors 4. MAO inhibitors

What are some positive activational effects of androgens?

1. Verbal Fluency 2. Spatial Navigation

Where does the central nucleus send information in accordance with the Amygdala stress response?

1. hypothalamus: activate HPA axis + sympathetic tone 2. Periaqueductal gray: increased avoidance 3. Diffuse modulatory systems: increased vigilance.

What is the phenotype for stress and depression on the body?

1. increased cortisol levels 2. increased adrenal gland size 3. cortisol effects on brain; change in transcription factors, growth factors, and glococorticoid receptors in the hippocampus 4. Hippocampal cell death

What is a typical nights sleep in terms of REM?

1st REM is about 10 minutes in duration after being asleep for about an hour. % REM increases over the course of the night. Last REM of night can be in the order of 30-60 minutes, and the amount of slow wave sleep is dropping as REM rises.

What is REM sleep?

25% of the time. Paradoxical sleep because EEG of someone in REM SLEEP is very ACTIVE than a regular EEG; it is desynchronized, and consists of Lower Amplitude, Higher Frequency EEGs; it is characterized by sympathetic activity and Atonia. MOST of REM is dreaming.

What is dream content?

60% about sadness, anger, and fear. 20% are described as particularly happy experiences. 10% are about sex.

What is Ghrelin?

A PEPTIDE released when the stomach is empty; ghrelin concentrations RISE before major meals (fasting periods), and stimulate the orexigenic circuits. There are Ghrelin receptors in the hypothalamus and the anterior pituitary.

What is the Serotonergic System?

A diffuse modulatory system originating in the Raphe nucleus; axons arising from here project to the forebrain, but given serotonin receptors are located throughout the brain, the system has widespread effects. This system is also involved in the control of MOOD. It fires most actively during wakefulness.

What is the Noradrenergic System?

A diffuse modulatory system that uses NE as its neurotransmitter. The core of neurons originate in the LOCUS COERULEUS in the pons; axons arising from here project throughout the brain, including the cortex, thalamus, and cerebellum. This system is generally excitatory, increasing responsiveness of brain cells, and becoming more active during attentive tasks and wakefulness.

What is the SRY gene?

A master gene in determining the sex of an embryo, whether it is born male or female. SRY=SEX determining region Y; it is located on the Y chromosome, and codes for TDF (TESTES DETERMINING FACTOR).This Master gene determines the expression of other genes that are also involved in sex determination (other sex genes may be on autosomes, and must be activated by sex genes on sex chromosome)

What is the suprachiasmatic nucleus?

A part of the hypothalamus that is important for regulating sleep/wake cycles, and responsible for controlling circadian rhythms

What is TMS and what can it be used to do?

A way to non-invasively change neural activity in humans using magnets; magnetic field can manipulate the electrical field in neurons; with TMS, can activate neurons, disrupt their activity, or induce plasticity to a degree.

What is a generalized tonic-clonic seizure?

A. Tonic Phase: limb stiffening; limbs get very tight as motor system is driven (person might even stop breathing) B. CLONIC PHASE: get on and off signal going to the motor system; yields jerking phase of limbs *CAN have one without the other, or have both; recovery could be minutes to hours. PERSON having one isn't conscious as there is a barrage of periodic activity across the entire cortex.

What is an epilepsy?

ABNORMAL, synchronous brain activity. It is a symptom, not a single disease or disorder. Most causes are UNKNOWN. Some forms are genetic; mutation involves dysfunctional ion channels and receptors that will affect the relative amount of excitation and inhibition. About 1% of people have epilepsy; 10% of adults will have 1 seizure.

What is the pontomesencephalotegmental complex?

ACh utilizing cells in the pons that provide ACh to the basal forebrain complex; part of the cholinergic complex; this complex is active during sleep

What do all abused drugs have in common?

ALL abused drugs similarly increase dopamine release in the nucleus accumbens. Hypothesis is that INCREASED dopamine levels are KEY features of addiction. Dopamine release provides motivation for those things essential for survival and what seems to be happening is that this system/circuit is co-opted for case of ABUSE

How do learning processes contribute to addiction? What experiment was done concerning this?

ANIMALS favor an environment in which they previously have received drugs; CONDITIONED PLACE PREFERENCE. Animals were placed in dual chamber environment; received drug in one side, and animals preferred to be on the SIDE where they received drug, showing that they have made an association between the room that they were in and the DRUG. Animals learn to associate neutral stimuli with drugs. Certain stimuli may act as REINFORCERS; behavior surrounding drug taking can trigger desire for drug itself.

What are the hypothalamic peptides implicated in feeding behavior?

ANORECTIC (inhibit feeding) •alphaMSH (alpha melanocyte stimulating hormone) •CART (cocaine-and amphetamine regulated transcript) OREXIGENIC (stimulate feeding) •Neuropeptide Y •AgRP (agouti-regulated peptide) •MCH •Orexins (hypocretins)

How is epilepsy treated?

ANTICONVULSANTS: increase inhibition and decrease excitation/excitability of neurons. These drugs may block sodium channels or enhance GABA function (inhibit breakdown), or block Glutamate receptors.

What are cooling mechanisms of thermoregulation?

APPROPRIATE BEHAVIOR: decrease activity, seek shade EVAPORATING HEAT LOSS: sweating, insensible water loss, panting; 1 g of water takes 580 calories of heat with it *Vasodilatation: this allows blood to access the skin surface, making it easier to get rid of HEAT

What are HEATING mechanisms?

APPROPRIATE BEHAVIOR: increase activity, seek shelter Shivering: mechanism to generate heat Vasoconstriction (heat conservation); pulls blood into core, decreasing heat loss from Surface Piloerection Brown Fat Catabolism: fat that generates heat

What is amnesia? What kinds exist?

Abnormal, abrupt, and serious loss of memory. 1. Retrograde Amnesia; forget past events (usually graded in time; tend to remember old things BEST) 2. Anterograde Amnesia: inability to form new memories

What is addiction? How do wanting and liking figure into this?

Addiction is a disorder of motivation. Distinction between WANTING and LIKING; liking is what we do for recreation, wanting is biologically based and is a CRAVING, something you are compelled to do. Wanting and liking are mediated by distinct processes and distinct brain regions. ADDICTIVE drugs tap into the wanting circuits in our brain to a powerful and pathological extent (even tapping into survival circuits; need drug to survive). In addiction, fatigue and disgust with something does not necessarily elicit avoidance.

What is HDAC2?

An enzyme that switches neuroplasticity genes off and therefore solidifies a memory; connections are no longer malleable and plastic

What experiment was done to show how novel objects become familiar?

An experiment was done where a monkey was presented with four never before seen faces and they plotted the response of a single neuron in the IT cortex. Initially, the neuron responds to all four faces equally, yield 20 spikes per second. over the course of the experiment as novel faces become familiar, the neuron starts to acquire a stronger response to ONE of those faces, an intermediate response to another, an a reduced response to the last two.

What sexual dimorphism does the Icelandic Stickelback fish display?

For the same body weight, the male brain is much bigger than the female; potentially associated with courtship and/or nesting behaviors.

What are negative activational effects of androgens?

Animals seasonal variations in androgen levels correlate with aggression. If immature animals are given more testosterone, they will display increased aggression as adults. Injecting testosterone in females increases aggression of female. Conversely castration decreases aggressive or assertive behavior.

How is panting a thermoregulatory mechanism?

Animals that dont sweat have to pant because they are using evaporative heat loss. Breathing IN ry air and expelling WET saturated air; releasing WATER releases HEAT

What is aphasia, and what kind of person is more likely to recover?

Aphasia is a disturbance of the comprehension and expression of language caused by a dysfunction of the brain. If someone suffers from a brain injury that yields aphasia in childhood, they will recover more quickly than someone whose aphasia occurs later in life.

How does age effect ocular dominance plasticity?

As age increases, ocular dominance plasticity decreases. The younger the animal, the greater the accomodation and plasticity (in this case, ocular dominance shift). At a certain point, there is a tapering off of the ability of ocular dominance columns to shift correctly, and beyond that, ocular dominance columns will not shift at all.

When does the SPEAKING critical period begin for humans?

At around 12 months; motor (inferior frontal) BROCA's AREA does not really show significant activity until 12 months; the babbling baby is doing in first year is important. Public health found that there is a correlation between the number of words a baby hears and its socioeconomic status

Why did they think putting TTX failed to yield ocular dominance shift?

BELIEVED that it was because when the retina is quiet, there wasnt input from RETINA to LGN so there was no noisy or dissimilar information going from LGN to cortex; therefore the cortex isnt receiving anything bad so it maintains connections; WRONG

What happens when neurons start dying as you age in terms of memory?

Because memory is stored in the unique pattern of activity across neurons, there is a more graceful loss of memory as neurons die; it is not catastrophic and immediate, but a more subtle confusion

How do neuronal responses change as novel stimulus becomes familiar?

Before learning, the neurons in the IT will respond equally to all faces. After learning, each neuron gains selectivity, and what it becomes MOST response to will vary. COMMON neural correlation of memory function--at the level of cells, the neurons will either gain or in some way modify their selectivity.

What effect did lesions on particular parts of the hypothalamus have on feeding behavior?

Bilateral lesions of the lateral hypothalamus caused ANOREXIA (severely diminished appetite). Bilateral lesions of the ventromedial hypothalamus caused the animal to overeat and become obese.

Canary Singing

Birds that sing seasonally in the spring; tend to change song throughout life. In spring, SURGE of testosterone (yearly activational effect) that makes VCRs grow in size; dendrites sprout and bird sings. In the fall, testosterone levels DROP, the VCRs shrink, and the animal stops singing. If a female canary is given testosterone as an adult, she will sing (shows doesn't need to be organizational effect; activational is sufficient)

What experiment illustrates the homeostatic nature of weight?

Body weight tends to be stable over long periods of time. When a rat was forced to go through periods of starvation, he lost weight. When allowed to eat again, he ate until he was back to his original natural weight, and didnt go above that. When the rat was force fed, he gained body weight, but when no longer force fed he dropped back down to normal weight. BODY WEIGHT CONTROLS FEEDING BEHAVIOR TO A LARGE DEGREE

How are AMPA and NMDA different?

Both are Glutamate-gated ion channels that allow the passage of cations. Glu binds to AMPA, the channel opens, and the target cell is depolarized by Na. Glu binds to NMDA, the channel opens, but when channel opens MAGNESIUM ION ENTERS THE PORE and CLOGS IT (silent receptor; open but blocked); for removal of block, the POSTSYNAPTIC MEMBRANE must be depolarized; NMDA ARE THEREFORE VOLTAGE DEPENDENT. NMDA is glu AND voltage-gated; when opened allows passage of BOTH SODIUM AND CALCIUM.

What is cortisol?

Cortisol is a hormone generated by the Adrenal Cortex and is released when the HPA axis is activated; it is a stress response lipophilic hormone that causes increased sympathetic tone, decreased immune response, and the dumping of sugars into the blood. Receptors for cortisol in fat cells and liver cells to regulate energy shifts in the body.

What are critical periods for language in HUMANS?

Critical periods for LANGUAGE suggested to start around TWO (WRONG). Research however has shown that Wernicke's area is active in newborns, and Broca's speech area is active by 12 months (babbling is important yo)

What happened when the cut off the neuromodulatory systems in the cat brain?

Cutting the connections of Ne and ACh diffuse modulatory systems to V1, when one eye was closed, a much greater percentage of the neurons continued receiving input from both eyes instead of shifting to receiving input from the working eye as is typical. When the neuromodulators are NOT PRESENT, do NOT see ocular dominance shift; inhibition of plasticity

What is indicative of working memory in terms of cell response?

DELAY PERIOD ACTIVITY: this maintained activity was seen in many cortical brain areas, and may be a general property of neocortex that allows brief period of maintained circuitry

What controls wakefulness and sleep?

DIFFUSE MODULATORY SYSTEMS. Have many brain stem systems that are in privileged position that are NOT good at giving specific signals from point A to B, but DO have access to huge swaths of the entire brain, and are good at MASSIVE and GENERAL changes.

What does DOPAMINE DO in terms of drugs?

DOPAMINE SIGNALS SALIENCE; it tells you something is IMPORTANT. REWARD (MOTIVATION) PLEASURE, EUPHORIA.

Why do we dream?

DREAMING DOES NOT seem to be essential. *You can dream in non-REM sleep but its distinctly different (more like a powerpoint) *Only in REM sleep do you have elaborate stories *If you have 2 weeks of REM deprivation in a human, don't see any harm of this *YET after deprivation, brain REBOUNDS to MORE REM • Why?!! Doesn't seem to be essential but brain seems to crave it for some reason

What are neuroleptic drugs?

DRUGS that reduce the positive symptoms of schizophrenia are potent blockers of dopamine receptors, specifically the D2 receptors in the mesocorticolimbic dopamine diffuse modulatory system. Neuroleptic dosages effective in controllingSchizophrenia correlate well with the drugs binding affinities for D2 receptors, partially because blocking dopamine receptors in the striatum could lead to symptoms of parkinson's disease.

What is the effect of decreased leptin levels on the hypothalamus?

Decreased leptin levels stimulates NPY/AgRP neurons in the arcuate nucleus which project to and activate the periventricular nucleus and the lateral hypothalamus. This causes increased feeling behaviors, decreased secretion of ACTH and CART, and increased parasympathetic activation. NPY/AgRP peptide neurotransmitters are orexigenic peptides

What is deep brain stimulation for the treatment of psychiatric disorders?

Deep brain stimulation of the ventral caudate nucleus in the treatment of OCD and Major depression

What are dendritic spines? How do they change when synaptic transmission is strengthened via increased NMDA activation?

Dendritic spines are little specialized compartments which receive synaptic input; might expect spine to get BIGGER to accommodate AMPA receptors when calcium flows in and causes the addition of AMPA to the postsynaptic membrane. Dendritic spines become around 30% bigger than they initially were during LTP.

What are DOPAMINERGIC Systems?

Diffuse Modulatory systems in the brain that arise from the substantia nigra and the ventral tegmental area. Axons arising from the substantia nigra project to the striatum, where they facilitate in the initiation of voluntary movement. Axons arising from the ventral tegmental area project to the frontal cortex and parts of the limbic system (reward system)

What are diffuse modulatory Systems?

Diffuse modulatory systems coordinate the activation states of neurons encompassing BROAD brain regions; a small group of neurons form the CORE of this system (often in brainstem); arising from this core, the axons spread widely across the brain, releasing neurotransmitter into the ECF so they can diffuse to MANY neurons where they activate metabotropic receptors.

What are the ROBUST FINDINGS in the brain regarding SCHIZOPHRENIA?

Dilated Lateral ventricles due to progressive loss of gray matter; loss starts in the parietal lobe and spreads to the temporal and frontal areas (dorsal lateral prefrontal cortex). HYPOACTIVE dorsolateral prefrotnal cortex; less focal activation of left prefrontal cortex + compromised at pre-frontal tasks. ALSO DECREASED DENSITY of SYNAPSES IN CORTEX

What are the positive symptoms of schizophrenia?

Disorganization: being perplexed and overwhelmed. Psychosis: delusions and hallucinations. MOOD INSTABILITY

What is TAMOXIFEN?

Drug used to treat breast cancer; it is an estrogen receptor antagonist, so while it fights cancer, it increases potential chances of STROKE (higher stroke risk)

What is the relationship between drugs and brain reward circuitry?

Drugs may activate brain circuits much more powerfully than natural reinforcers; cause adaptations that DO NOT HAPPEN with natural reinforcers. Adaptations: there are molecular, cellular, and synaptic changes in the circuitry that may lead to addiction; addicted brain is physiologically NOT THE SAME as non-addicted brain. CHEMISTRY has changed.

During wakefulness, what is the status of diffuse modulatory systems?

During wakefullness, Ne, 5-HT and ACh are all very active, while during sleep time, they are less active.

How can critical periods be made to shift?

ENVIRONMENTAL CHANGES 1. Put animal in dark 2. Give animal drugs that break down ECM; allows more room for neuron growth 3. Prozac: less inhibition, more plasticity 4. Environmental enrichment; POTENTIALLY (?)

What are the protective effects of estradiol?

Estradiol has potent protective effects for neurons; neurons more likely to survive HYPOXIA (oxygen deprivation) if estradiol is present (decreased stroke damage?). May LESSEN the effects of Alzheimer's, MS, and Parkinson's disease.

What activational cycles do females go through? males?

Females: follow menstrual cycle; fairly regular Males: rapidly fluctuating hormone concentration throughout the day (rise at sex-related thoughts, aggressive behavior, stress, etc.) *Connection between sexual behavior and hormone levels

How does cortical plasticity occur between sensory modalities?

Found that in blind people, the occipital lobe began to be used for somatosensory purposes, like reading braille. Interesting phenomenon that one entire brain area that is not being used can be taken over by a DIFFERENT MODALITY all together to imrpove the senses of the perceptions that remain

How does ERYTHROPOIETIN effect chronic schizophrenia?

Found that recombinant human erythropoietin delays loss of gray matter in chronic schizophrenia. Found that weekly high doses of EP for as little as 3 months halts the progressive atrophy in the brain areas typically affected by Schizophrenia, including the hippocampus, amygdala, nucleus accumbens, and several neocortical areas.

What is sex determined by?

GENETICS and HORMONES; genetics influence the development of later traits largely through hormones. Humans have 46 chromosomes, 44 pairs of autosomes and 2 sex chromosomes. XX is female, XY is male. X is larger than Y, with 800 to 50 genes on the chromosomes respectively.

What is the reality about the assumption that the critical period of language for HUMANS ends at puberty?

GRAMMAR and ACCENTS have short critical periods, while VOCABULARY and semantics have longer critical periods/less defined critical periods.

What is the negative reinforcement system for eating?

Gastric Distention, CCK, acute blood changes, etc. all stimulate you to STOP eating; negative reinforcement is activated despite there having been no change regarding taste and smell.

What is the OB gene?

Gene that generates LEPTIN. Found that DNA of one strain of obese mice lacked copies of OB; in the mice that lacked this gene and therefore the leptin hormone, the brain fooled itself into thinking that the fat reserves were low, and the animal was motivated to eat. Treating animal with LEPTIN reversed the effect.

What is GPI?

General Paresis of the INSANE. Initially was considered a psychiatric disorder; has symptoms consistent with mental deterioration (mania, delusions, asocial behavior, etc). discovered it was SYPHILLIS. once bacterial origin of disease was realized, shifted from being considered a psychiatric disorder to a neurological one.

What controls the genes that are important for memory consolidation?

Genes are controlled by CREB PROTEIN; CREB is a transcription factor that binds DNA; when phosphorylated, gene transcription will take place (potential key to unlocking basis of learning and memory).

What is the PRADER-WILLI Syndrome?

Genetic cause of obesity; it occurs in people with defect in chromosome 15; they never feel full and therefore constantly eat; fasting levels of Ghrelin are elevated + above normal

What is the GHRELIN mechanism?

Ghrelin excites the orexigenic circuit. It excites the NPY/AgRP neurons of the arcuate nucleus, which stimulate the lateral hypothalamus area, which stimulate feeding behavior. it also INHIBITS the anorectic circuit

How does the brain respond to food v. drugs?

Graph shows the relationship between DOPAMINE levels measured in the nucleus accumbens in response to FOOD, and also in response to COCAINE. FOOD: when feeding, dopamine levels rise to 150 or so; naturally rewarding stimulus; DA levels start descending and return to normal levels after 3 hours. COCAINE: % of basal dopamine release is 3 fold compared to food; it has a MUCH GREATER effect than naturally rewarding stimulus; more than 300%, and doesnt drop to baseline after 5 hours; for 3 hours levels are still RISING. Long treatment of postsynaptic cells to dopamine play important role for setting up actual adaptions + changes.

Why do we eat?

HEDONIC: it feels good DRIVE REDUCTION: we are hungry

What is sexual orientation in humans?

HETEROSEXUAL MALES tend to have an INAH3 that is about 2x the size as in females; reports that INAH3 in gay men is about half the size that it is in straight men; more similar to the size of FEMALES than males.

What do Hallucinogen's resemble, and why is that important?

Hallucinogens, such as LSD, have similar structures to serotonin, and tend to bind to endogenous serotonin receptors, acting as a very potent agonist

What is the PARASYMPATHETIC system like?

Have many preganglionic cells located in the brainstem; these cells are CHOLINERGIC; they make synapses on parasympathetic ganglia next to each target organ; the post-ganglionic cells also make ACh, and release ACh onto the target tissue

What can happen when there is continuous exposure to cortisol?

Hippocampus can SHRINK. Chronic stress can cause the hippocampal neurons to wither and die in experimental animals; this is also shown in people with PTSD who have smaller hippocampus brain regions than "normal" people

What is homeostatis, and what part of the brain maintains it?

Homeostasis is the maintenance of the body's internal environment within a narrow physiological range; it is regulated by the hypothalamus in response to the changing external environment

What are sex hormones?

Hormones released by the ovaries and testes that are ultimately under the control of the hypothalamus and the pituitary. Males and females have the same sex hormones but in vastly different concentrations. Sex hormones are crucial to the development and function of the reproductive system and sexual behavior.

What is the HPA axis, and what are the effects of this on the body?

Hypothalamic-Pituitary Adrenal Cortex Axis. It is involved in the stress response, and ultimately generates the production of CORTISOL.

What does the process of becoming addicted require?

Hypothesis: the process of becoming addicted requires glutamate synapse neuroplasticity. ➢ Addiction as a form of experience-dependent plasticity • Uses mechanisms also used in LTP; requirement for NMDA activation at glutamatergic synapse, which lets calcium in; results in introduced of AMPA receptors • Same amount of glutamate being released causes greater postsynaptic response after increase in # of AMPA receptors

What stimulates drinking behavior?

Hypovolemia: a decrease in blood volume Hypertonicity: increase in the concentration of dissolved substances

How can meditation cause experience dependent plasticity?

INCREASE in gray matter in posterior cingulate cortex, temporo-parietal junction, cerebellum, and hippocampus. Changes in gray matter in areas for learning and memory, emotional regulation, self-referential processing, and perspective taking; increased positivity

What has happened if we place ICE in the mouth of a normal person?

Ice will COOL blood in the carotid artery, which cools the hypothalamus; this activates heat production mechanisms, causing the core body temperature to rise, which warms the blood ascending to the hypothalamus, and therefore serves to regulate heat production.

What happens when the blood is hypertonic?

If blood is hypertonic, the osmotic pressure is HIGH; this pressure and high concentration of solutes in the blood will be detected by OVLT neurons, causing vasopressin to be released, which keeps you from urinating

Why have critical periods at all? Why have experience-dependent plasticity rather than having a pre-wired system?

If the environment that the animal is going into might be variable, want to let animal experience environment before determining what is MOST important for the CNS

What happens if the dopamine receptors in the nucleus accumbens are blocked?

If you block dopamine receptors just in the nucleus accumbens, you have reduced self-administration.

What if you cut the pathways between the VTA and nucleus accumbens?

If you cut the pathway between the VTA and nucleus accumbens, thereby reducing the innervation and administration of dopamine in this pathway that synapses and is released into the NA, the animals will REDUCE their self-administration.

What do you tend to forget more often in terms of time?

If you forget things, you will forget the MOST recent memories and the OLDER things you will be more likely to retain; hypothesis is that the distinction is that things in short term memory are MORE SENSITIVE while those in long term are older and harder to disrupt; there is a CONVERSION PERIOD where things get MORE and MORE permanent

What are pyrogens, and what is their effect on the preoptic nuclei?

If you get an infection, the infecting organism and your own body ultimately generate a LOT OF CHEMICALS, which drive the body temperature up; increasing temp is a response to infection because it allows body to fight better. RAISES SET POINT so that high temperature can be maintained

Under what conditions can a female Zebra Finch sing?

If you give testosterone to an ADULT female Zebra Finch, she will not sing. If you give testosterone to a developing Zebra finch it will not sing. If testosterone is injected both organizationally and activationally, then it will sing an will generate larger VCRs; brain becomes more male-like over time. This shows the effect of HORMONES on brain structures and brain composition overall.

What is the status of cholinergic neurons during REM?

In REM SLEEP, have an increase in the activity of acetylcholine neurons coming from the PONS; a subset of the acetylcholine diffuse projecting neurons. The diffuse systems project to neocortex and to the thalamus.

What is IMPRINTING in birds?

In ducklings, whatever the animal sees first, it IMPRINTS ON and assumes that the animal is its mother. Imprinting is important for a duckling because that's how it knows who will take care of it; these animals have a very SHORT CRITICAL PERIOD; once it imprints on something, it will NOT imprint on anything else.

What was the experiment done to determine LTP?

In hippocampus, had microelectrode placed in the CA1 neuron; they put stimulating electrodes on either side of the neuron and applied brief electrical shocks; applying shock to left side of neuron activated a set of neurons (input 1), and to the right a different set of neurons (input 2). Found that can invoke stable response by shocking right/left/right/left. THEN shocked in HIGH FREQUENCY BURSTS; had brief burst of activity applied only to input 1, and then RESUMED baseline stimulation; the response was elevated for input 1, and synaptic strengthening was elicited.

What is the effect of elevated leptin levels on the hypothalamus?

Increased leptin stimulates alphaMSH and CART neurons in the arcuate nucleus, which project to and inhibit the activation of the lateral hypothalamus, serving to decrease feeding behavior, increase TSH and ACTH levels (increased metabolic rate in cells), and increase sympathetic innervation. AlphaMSH and CART are anorexic peptides (diminish appetite)

What if the amount of vasopressin receptors are increased in montane voles?

Increasing expression of vasopressin receptors makes montane voles more monogamous. Viral vector was used to express the gene encoding for vasopressin receptor in the Ventral Pallidum. Shows how changing ONE GENE completely changes complex mate-selection behavior (activation of reward pathway involved)

What is working memory?

Information "HELD IN MIND." Has a very limited capacity; duration is in seconds; rehearsal is required to maintain memory, and is very easily disrupted; more ELECTRICAL ACTIVITY as opposed to permanent neural change.

What is a possible function of the prefrontal cortex in terms of memory?

Involved in learning and memory; when lesioned, there is a marked decrease in proficiency at delayed response task experiments, and a difficult on Wisconsin card-sorting test

What are the two parts of the cholinergic system?

It is a diffuse modulatory system that consists of: 1. BASAL FOREBRAIN COMPLEX 2. PONTO-MESENCEPHALO-TEGMENTAL COMPLEX

What does the effect of AGE on plasticity suggest?

It suggests that there are neurodevelopmental critical periods; certain ranges of time during a person's life where they have MORE plasticity

What did the study of aplysia find?

Kandel recorded changes in synaptic transmission that occurred in brains in aplysia as they occurred, and found that synapses DO MOTIFY

What is Amblyopia?

LAZY EYE: detecting the condition in early childhood increases the chances of successful treatment.

What is learning and memory?

LEARNING: the acquisition of NEW INFORMATION or knowledge. MEMORY is the retention of learned information.

What happens when the nucleus accumbens is lesioned in self-administration experiment?

LESIONS of the nucleus accumbens will halt self-administration; shows that drug is directly acting on that area to bring about the reinforced behavior (as well as VTA).

What is REM sleep behavior disorder?

LOSS of REM ATONIA: acting out their dreams in some way because they can still move. The cause is unknown, but lack of atonia is associated with STROKE or TUMORS. 90% of people who have this are older men, and it tends to have co-morbidity with Parkinson's disease.

What is the mechanism of getting rid of these AMPA receptors similar to?

LTD: Long Term Depression. Decreasing strength of post-synaptic neuron and synaptic connection in general by removing AMPA receptors. If we give animal drug that BLOCKS NMDA receptors, we can prevent ocular dominance column shifts

How is LTP triggered?

LTP is triggered by STRONG activation of NMDA receptors; these are glutamate gated ion channels that allow the passage of calcium and sodium; and the synaptic connection is strengthened when the calcium flux signal is coincident for both PRE and POST synaptic activation.

What is the neurobiology underlying drug abuse and addiction?

Laboratory animals will self-administer drugs often to great excess (DEATH); rather receive drug over eating and drinking; similar in humans who will choose to do drugs over what is good for them. Animals will WORK to receive drug (press lever MANY TIMES to get single infusion), and will tolerate pain and distress (will keep self-administering despite receiving shocks). Amount that animal will self-administer drug will correlate with the addictive potential for that drug in humans.

What are the major satiety signals?

Largely originate in gut + intestines. 1. Gastric and Gut distension. 2. CCK 3. Rise in blood levels of Glucose 4. Rise in blood levels of Insulin

What is LEPTIN?

Leptin is a hormone (satiety) made by the ob gene in FAT CELLS which regulates the amount of fat stored in the body (weight regulation). It does this by affecting hunger and energy expenditure. Blood levels of leptin are proportional to the body fat mass in humans.

What is the structure of the hippocampus?

Lies on medial side of temporal lobe. The Hippocampus is bordered by the entorhinal cortex (which is adjacent to the rhinal fissure). It has two interlocking parts, the dendrate gyrus and ammon's horn. In the perforant path, the entorhinal cortex gives rise to axons that penetrate into the hippocampus proper and form synapses on dendrate gyrus. Dendrate gyrus neurons synapse onto CA3 neurons; CA3 neurons divide into branches, with one branch leaving the hippocampus as a huge fiber bundle (FORNIX), while the other branch continues in the hippocampus, CA1. Hippocampal cortex only has 1 cell layer.

How are morphine and heroin different?

Morphine is a fantastic pain-reliever; vast-majority of hospital patients who use it are NOT addicted. However, heroin, which reaches the brain much faster than a dose of morphine, even though when it crosses the blood-brain barrier it BECOMES morphine, is MUCH MORE ADDICTIVE. Heroin suddenly RAMPS UP in your brain and stays there for a very long time

Electroconvulsive therapy?

Most effective treatments for depression and mania that involves inducing seizure activity in the temporal lobe; an adverse is potential memory loss, but allows memory recovery QUCKLY

What is the result of naturally rewarding stimuli?

NATURAL REWARDS increase dopamine levels in the nucleus accumbens. FOOD and SEX both have increased DA concentration. Naturally rewarding stimuli, things we need for survival, which are important for us as an individual and as a species, the BRAIN has evolved do drive us towards these actions; dopamine might be the signal REINFORCING these things

What is the time course for schizophrenia?

NEUERODEVELOPMENTAL DISEASE. The emergence of the symptoms coincide with the windows of changing brain chemistry (the critical periods) that occur naturally.

When does the listening critical period begin for humans?

NEWBORNS: A baby in an MEG shows active Wernicke's area when someone is talking; AUDITORY superior temporal Wernicke's area

Why is the gating of NMDA important?

NMDA is both glutamate-gated and voltage-gated, and in that way it acts as a COINCIDENCE DETECTOR (determines if pre and postsynaptic neuron are in sync. Current only flows when the presynaptic synapse is active at the same time that the postsynaptic membrane is strongly depolarized.

Why is there less plasticity when synaptic transmission matures?

NMDA receptors change from ones that are conducive to plasticity to NEW NMDA receptors that have different molecules which inhibit neuroplasticity. This is about STABILIZATION: if you've figured out your world, dont want brain to change at every little shift; allow brief period for environment to influence you, and then beyond that be efficient with processing by having things hardened into place

What is neuromodulation?

Neuromodulation occurs through the use of diffuse modulatory systems, and is necessary for plasticity to occur. Two main neuromodulators are Ne and ACh (Noradrenergic + cholinergic) systems

What does it mean for cortical activation to be constrained?

Neuromodulator systems ultimately effect the overall levels of cortical activity; once these have been constrained, it is harder for cortical plasticity to occur.

What senses hypertonicity of the blood?

Neurons in a specialized region of the telencephalon lacking a blood-brain barrier, the VASCULAR ORGAN OF THE LAMINA TERMINALIS (OVLT) • When blood becomes hypertonic, water leaves cells by the process of osmosis; the loss of water is transduced into a change in action potential firing frequency by OVLT neurons • The OVLT neurons directly excite the magnocellular neurosecretory cells that secrete vasopressin, and stimulate osmometric thirst, the motivation to DRINK WATER

What is hypocretin?

Neurons in lateral hypothalamus project WILDLY to the brain. Interact with diffuse modulatory systems; the net effect is to make brain more AWAKE

Where is each drug acting in order to increase release of dopamine?

Nicotine can increase the release of dopamine by acting directly on DA cells. Alcohol + opiates are known to act on GABA receptors, inhibiting gabanergic neurons, allowing dopaminergic neurons to fire more (since GABA neurons are inhibitory). Psycho-stimulants (cocaine and amphetamines) act on dopamine terminals.

What did the experiment yield in which one of the monkey's eyes was sutured shut at a very young age (monocular deprivation)?

Ocular dominance columns SHIFTED + displayed plasticity. The parts of the non-seeing eye in Layer IV diminished considerably while the seeing-eye cortical representation in the striate cortex expanded in width

What if vasopressin or oxytocin antagonists are injected into the monogamous VOLES?

Oxytocin receptor antagonists injected into the Nucleus Accumbens or Pre-Limbic Cortex prevent partner preference in Monogamous voles

What is non-declarative memory?

PROCEDURAL MEMORY or CLASSICAL CONDITIONING; skills and habits, unconscious memories that you do not articulate; they are hard to learn and hard to forget. OFten involves more motor related structures like striatum, cerebellum, and amygdala.

What is the neurobiological basis of transition to long-term memory?

PROTEIN SYNTHESIS. When rat was trained in inhibitory avoidance (IA), they found that even with one experience the animal had a very stable memory because it had been consolidated into long term memory storage. HOWEVER, if the animal is injected with a drug that blocks new protein synthesis, the animal will learn fine, but the MEMORY WILL FADE; memory decays if protein synthesis is inhibited because it is what allows consolidation to occur.

What are factors that effect the set point?

PYROGENS HORMONES SLEEP: during sleep our body temperature drops SKIN RECEPTORS

What is referred pain?

Pain that is associated with the lost limb can be felt on a different part of the body because those two places are on adjacent parts of the somatosensory cortex; stimulating one may inadvertently stimulate the other

What are anxiety disorders?

Panic, phobias, and OCD. It is extremely common, and typical symptoms include increased vigilance, avoidance, and sympathetic activation + HPA axis activation. Lifetime prevalence is 28%.

What is ROID RAGE?

People who use anabolic steroids in order to build muscle (activational effect) by mimicking the naturally occurring androgens in the body tend to exhibit overly aggressive behavior and loss of impulse control

What is characteristic of bipolar disorder?

Periods of severe depression and mania interrupted by periods of hypomanic activity. Feeling depressed, normal, and then MANIC. Hypomania is JUST below manic, and is when you are full of energy and drive, while simultaneously organized and capable. During mania, you are HIGH ENERGY, but aren't really functional nor present.

What are place cells in the hippocampus?

Place fiels are similar to visual receptive fields; the cells respond to location relative to visual cues; but they are not PURELY visual, they do not occupy an absolute position in space; place cells appear to respond based on where the animal THINKS IT IS. Place cells are also dynamic; they have the ability to change/move and may be valuable for radial maze task

What happens to a sensory system when there is a LOT OF INPUT? ex: violin

Players use left hand fingers a LOT; changes occur in contralateral portion of the brain; there is increased representation of the more USED parts of the body; playing violin changes and reorganizes S1. Violinists use pinkies a lot; have greater capacity to recognize fine stimulus at this fifth digit than control people

Is there any evidence that learning induces LTP? What experiment was done?

Rodent was put in box with two chambers, light and dark. Mice prefer dark so scurry to that side, but when they do a mild foot shock is applied. Inhibitory avoidance conditioning is a VERY ROBUST form of memory; when mouse is put into box, he will not go over to dark side. They recorded from mice in vivo synaptic transmission in the hippocampal circuit and found that synaptic transition changed when the animal learned to avoid the dark side; strength of synaptic transmission jumped up drastically

What factors into memory?

SALIENCY and emotion factor into whether brain will store events

What is sexual orientation in rats?

SDN is larger in males. if SDN is lesioned, rat will spend more time will males rather than the females it would have spent more time with; prefer male-male interactions over male-female

What brain dimorphisms exist in RATS between the sexes?

SDN: sexually dimorphic nuclei; it is a preoptic area of the anterior hypothalamus. Found to be 5-10x bigger in males than females. If you give testosterone to an adult rat, the SDN will GROW

What is the hippocampus involved in?

SHORT TERM MEMORY CONSOLIDATION SPATIAL MEMORY Hippocampus is involved in linking information, especially between different sensory modalities.

What is the physical basis of memory storage? What changed that enabled neuron to go from non-selective state to selective state?

SYNAPTIC CONNECTIONS! Synapses carrying one form of information will get STRONGER as synapses carrying another will get weaker. It is these INCREASES and DECREASES in synaptic strength that can store information; changing synaptic connections is important, and memories are equally well stored by either decreases or increases in synaptic strength.

What is long-term potentiation and how does it happen?

SYNAPTIC STRENGTHENING; it only occurs at the synapses that get STRONG STIMULATION (homosynaptic). LTP is elicited with a brief experience but it can last a very long time.

How does salience affect the brain?

Salience has widespread affects on the brain and can yield consolidation; can often occur via activation of DIFFUSE neuromodulatory systems. Neuromodulatory systems have routed communication to the neuron's nucleus, and cause new gene expression; the mRNAs then leave the nucleus and are used to direct protein synthesis; and LTP is consolidated by protein synthesis, so salience is conductive to memory formation

What is the glutamate hypothesis of schizophrenia?

Schizophrenia has many of the same symptoms as taking the drug PCP; PCP has no effect on dopaminergic transmission. Rather PCP acts by inhibiting NMDA receptors, affecting synapses that use glutamate as a neurotransmitter. so hypothesis suggests that disorder reflects diminished activation of the NMDA receptors in the brain.

How does the physical appearance of the brain differ in twins, one with schizophrenia, one without?

Schizophrenic sibling had enlarged lateral ventricles (shrinkage of brain tissue). Often have defects in myelin sheath surrounding axons in their cerebral cortex. abnormal clusters of neurons.

What are SSRI's?

Selective Serotonin Re-Uptake Inhibitors (such as PROZAC or ZOLOFT) are effective drugs against clinical depression. When your brain releases serotonin regularly, some is immediately taken up from the synaptic cleft; re-uptake inhibitors prevent this and allow serotonin to remain in the cleft LONGER, improving MOOD.

What are SSRIs?

Serotonin-Selective Reuptake inhibitors. They act to prolong the actions of released serotonin at their receptors by inhibiting reuptake. therapeutic effects develop slowly over a period of weeks in response to regular daily dosing.

What was the effect of the size and location of the lesion on memory in the rats navigating the maze?

Severity of the deficits caused by the lesions correlated with the size of the lesion, but were apparently unrelated to the location of the lesion within the cortex.

What is schizophrenia?

Split mind. 1% of world population. 50% co-morbidity in identical twins. HUGE genetic link in this disease. incidence and severity are higher in males than females.

What are sex hormones derived from? What property does this denote?

Sex hormones are steroids; steroids are synthesized from cholesterol and have FOUR CARBON RINGS; they are fatty and can easily pass through cell membranes and bind to receptors within the cytoplasm, giving them direct access to the nucleus, allowing them to effectively modulate gene expression

What is the difference between sex and gender? Gender identity?

Sex: the biological state of being male or female. Gender: a social construction of the roles associated with being male or female; defines what it means to be masculine or feminine within a certain cultural sphere. Gender identity: our perception of our gender, which may or may not match our sex, and the gender norms associated with our sex

What is sexual orientation in ROCKY Mountain Big Horn Sheep?

Sheep bash their brains against each other with gigantic horns. 8% will try and mount other males but NOT other females. The male-mounting sheep have an SDN that is about HALF the size of that compared to other males. SDN seems to correlate with male/female affinities.

How do skin receptors effect the preoptic nuclei?

Skin receptors allow the body to PREDICT that it is going to GET cold or hot; it can kick in mechanisms to prevent body temperature from changing

What is sleep, and what are potential reasons for why we do it?

Sleep is a restful loss of consciousness; presumably important because all animals become vulnerable and do it. 1. RESTORATION (REST & RECOVER) 2. ADAPTATION for SAFETY (protect from predators by laying low; ensured silence) 3. CONSERVE ENERGY (colder at night; mini-hibernation)

What experiment showed that LTP and LTD mechanisms exist in HUMAN BRAIN?

Sometimes neurosurgeons have to disregard diseased parts of cortex in epileptic patients; researchers study tissue and prepared brain slices to study synaptic plasticity in the inferotemporal cortex; they found that low frequency stimulation produces LTD and high frequency stimulus produces LTP.

What test was done regarding LEG AMPUTATION?

Tested two-point discrimination on area just above amputation. Found that people who had phantom limb also had finer two-point discrimination, indicating that the lack of sensory input allowed changes not just in terms of growth of area in the somatosensory cortex, but fundamental change in the size of the receptive fields (smaller receptive fields possible because more room in somatosensory cortex); improved sensory discrimination only occurred when the person had phantom percept

What ultimately determines whether there is LTD v. LTP? How so?

The AMOUNT OF NMDA RECEPTOR ACTIVATION determines the result. Strong and weak NMDA receptor activation recruit different calcium-dependent enzymes. LTP is triggered by calcium-activating protein kinase; while LTD is triggered by calcium dependent phosphatases. If you weakly activate the NMDA receptors, can selectively activate phosphatases that take phosphate groups OFF because they have a higher affinity of calcium, which ultimately causes removal of AMPA from membrane. But if there is a lot of calcium, there are more kinases, so LTP will result.

What is the RETICULAR ACTIVATING SYSTEM?

The Serotonergic System and the Noradrenergic System; the locus coeruleus and the raphe nucleus together form the reticular activating system, which controls sleep/wake cycles, activation/de-activation of the forebrain, and is found to RAMP UP when you are awake

How quickly does ocular dominance shifting occur? How is this quantified?

The amount of AP produced by the left and the right eye are usually equal; when one eye was deprived of visual input for 17 hours, after this time it displayed DECREASED AP when looking at stimulus; there was a change at the level of neurons and how it responds to particular input

How is the stress response controlled by the Amygdala?

The amygdala is critical to the fear + stress response. Information from the neocortex and thalamus synapses on the amygdala, is integrated in the basolateral nuclei, and then relayed to the central nucleus. Activation of the central nucleus leads to stress response. Central nucleus will activate the hypothalamus, periaqueductal gray, and diffuse modulatory systems

What happens when you are stressed?

The hypothalamus will release CRH (corticotropin releasing hormone), which tells the anterior pituitary to release ACTH. ACTH travels to the Adrenal Cortex (which sits atop your kidneys). Cells in adrenal cortex have receptors for ACTH, and when activated, they then release cortisol into the bloodstream, which then acts throughout the body to mobilize energy reserves and suppress the immune system, etc.

What is MEMORY consolidation?

The idea that memories are stored in short term memory and are SELECTIVELY CONVERTED into a permanent form via MEMORY CONSOLIDATION. Consolidation process is ENHANCED by salience and emotion

What is the dopamine hypothesis of schizophrenia?

The idea that psychotic episodes in schizophrenia are triggered specifically by the activation of dopamine receptors (especially D2). There is a link between the mesocorticolimbic dopamine diffuse modulatory system and schizophrenia. Ventral tegmental area is part of the reward system and projects to the prefrontal areas and modulates activity there

What is the lipostatic hypothesis?

The idea that the brain monitors the amount of body fat and acts to defend this energy stored against perturbations.

What are magnocellular neurosecretory cells?

The largest of the hypothalamic neurosecretory cells whose axons extend into the posterior lobe. They release TWO neurohormones into the bloodstream, oxytocin, and vasopressin.

How does gut distention signal satiety?

The stomach wall is richly innervated by mechanosensory axons, stretching of wall innervates axons; Gut distention yields vagal activation; activation of vagus nerve stimulates the NTS and influences feeding behavior, yielding satiety signals

What did the experiment concerning the hypothalamus and the fMRI yield?

The study consisted of an fMRI of a mother looking at her infant; they found brain activity in oxytocin-binding regions + brain's reward pathways. Similar areas activated between maternal love + romantic love (when looking at partner)

What is the effect of leptin on the brain?

There are leptin receptors in the brain, particularly in the arcuate nucleus of the hypothalamus. Leptin serves to regulate body mass by acting directly on the neurons of the hypothalamus to decrease appetite and increase energy expenditure

What do parvocellular neurosecretory hormones secrete?

These neurons secrete HYPOPHYSIOTROPIC hormones into a uniquely specialized capillary bed; these tiny blood vessels run down the stalk of the pituitary and branch in the anterior lobe, where they bind to specific receptors on the surface of pituitary cells, which causes the secretion or cessation of secretion of hormones into the general circulation

What did researchers hypothesize concerning benzodiazepine receptor density in patients with anxiety or panic disorders?

They hypothesized that there were fewer/a lower density of benzodiazepine receptors in people with panic disorders so there ultimately would be increased firing of AP, and maintained activation of stress circuits. In a PET scan, they found that, especially in the frontal cortex, there were many fewer binding sites for benzodiazepine in the individual with the panic disorder. Adding MORE benzodiazepine and increasing the activity of the existing benzodiazepine receptors is a way of balancing out the effect of reduced receptors.

Are human brains dimorphic?

To some extent, yes. I INAH: interstitial nuclei of the anterior hypothalamus; there are four of these; 1,2, and 4 are slightly larger in males, while INAH3 is SIGNIFICANTLY larger in males (human SDN?). Besides this, there are many subtle male and female brain differences, but ultimately these are small, and the relationship to behavior is unclear.

How do BENZODIAZEPINES WORK?

Treat anxiety disorders by binding to modulatory sites on GABA-receptor ion channels, serving to make GABA much more effective in opening the channel and producing inhibition by allowing chloride ions into the cell, yielding hyperpolarization and IHIBITION. The calming action of benzodiazepines are due to the suppression of activity in the brain circuits used in the stress response. Bind to Gaba-gated chloride channels and have allosteric effect, making the channels more responsive to the GABA that is released normally at the synaptic cleft, maintaining negative membrane potential.

Under what conditions will weak events be consolidated?

Weak events are consolidated if they occur proximal to strong ones. If you follow weak stimulation with strong stimulation onto the same neuron, can consolidate not only synapses involved in STRONG, but also synapses that were activated in recent past; triggering protein synthesis. That is why you remember minute details of a traumatic event. Memories that WOULD have faded are RETAINED.

What is the experiment concerning how LTP relates to memory consolidated by protein synthesis?

Weak tetanus yields LTP that eventually decays back to baseline. STRONG stimulation yields STABLE LTP; strong stimulus can produce protein synthesis (required for LTP to be CONSOLIDATED)

Why does TTX result in the striate cortex failing to yield an ocular dominance shift?

When TTX was put in the eye of an awake animal, the RETINA was silenced, but the LGN was firing; LGN receives 20% of input from retina and 80% from cortex; LGN yielded patterned firing that while not equivalent with what the firing would be if eye was open, was not random and without patterned-element.LGN would have small spontaneous bursts of activity (high firing rate of fAP for a short period of time)

What did they find in terms of how many neurons in binocular layers of V1 (layers II and III) respond to both eyes vs. one eye?

When both eyes are used, in the binocular layers of the striate cortex (II + III) they found that the neurons responded to the different eyes in varying degrees (completely ipsilateral, completely contralateral, or somewhere in between). When there was monocular deprivation, the neurons switched so they only responded to the SEEING EYE; the experience of having the eye closed changed the response properties of these neurons; changes do not require that animal have ocular dominance columns (shift will occur without)

When are females most likely to initiate sex?

When estradiol levels are HIGH; illustrates the activational effects of hormones and how sexual behavior is linked to hormone concentrations

What is the effect of CCK?

When food enters stomach, the gallbladder is stimulated to release CCK; this causes bile to enter the GI tract to help digest food; CCK is a potent inhibitor of eating behavior in the brain. CCK inhibits meal frequency and SIZE; it is released in response to stimulation of the intestines by certain types of food, especially FATTY ONES; major action of CCK as a satiety peptide is exerted on the vagal sensory axon. CCK acts synergistically with Gastric distention

What is ATONIA?

When in REM SLEEP, people dispaly atonia which is when they are unable to MOVE; happens because there is descending inhibition of lower motor neurons. This inhibition primarily effects BIG muscles more than smaller muscles (Can still move eye muscles, fingers, etc)

How does ocular dominance plasticity happen mechanistically?

When seeing something, the neighboring neurons of the retina will be firing in a patterned manner; this yields strong NMDA receptor activation by well-correlated activity, which maintains high density of AMPA receptors. NMDA receptors activate when there is a nice correlation between pre and post-synaptic activity. When you have a CLOSED EYE, there is weak NMDA receptor activation by poorly correlated (lacking patterned AP) activity which triggers LOSS of AMPA receptors, and decreased response

What happens when the neurons fire out of sync?

When the synaptic activity of a neuron consistently fails to correlate with a strong postsynaptic response, the synapse is weakened or eliminated. LOSE THEIR LINK YO

What is RECONSOLIDATION?

When you RECALL a memory, the act of conjuring it back up makes it PLASTIC again in a way that it wasnt when it was stored and untouched. Means that the reactivation makes memory malleable. Long term memory is NOT as stable as once thought.

What happened when there was electrical brain stimulation during epilepsy surgery?

Wilder Penfield would stimulate different parts of brain. Found that during epilepsy, some would have an aura associated with them; have a SENSORY EXPERIENCE prior to an epileptic attack

Can the mechanisms of LTP and LTD account for memory acquisition?

YES THEY CAN; theoreticians have studied neural network models with rules of LTP and LTD and these models do well producing features of memory; COOPER developed BCM theory

Is sleep essential in humans? What is the longest documented case of remaining awake?

Yes; Randy Gardner decided to see how long he could stay awake; on the order of 11 days; he is considered the best documented longest term awake; he had hallucinations after a while; tremors; speech difficulty (slurring); did it without any stimulants (no artificial means); did recover afterwards. RAT experiment where they were prevented from sleeping; they lost weight, lost ability to thermoregulate appropriately, developed infections, and died.

Do all cortical areas contribute equally to memory?

all cortical areas DO NOT CONTRIBUTE EQUALLY TO MEMORY, but memories are distributed

What is LITHIUM?

an ion/salt that has mood-stabilizing effects. A highly effective stabilizing treatment for mood disorders of patients with bipolar disorder by preventing not only the recurrence of mania but also the episodes of depression.

What is phantom percept?

if you lost a limb, may still have sensation coming from that lost limb; found that increase in two-point discrimination only occurred in those who had the phantom precepts.

How is the HPA axis regulated?

it is activated by the Amygdala (fear + emotion), and inhibited by the hippocampus, which has many cortisol glucocorticoid receptors so acts in a negative feedback system to downregulate the stress response and inhibit CRH release.

What are the negative symptoms of schizophrenia?

lack of engagement, lack of interest, lack of pleasure

What is the default mode network?

network that plays a putative role in introspection and consciousness. it involves the PREFRONTAL CORTEX, the parietal cortex, and the cingulate cortex; these are the areas of the brain that maintain activity when a person is told to relax and calm down. When the person is asked to perform specific tasks, these systems are regulated down in order to FOCUS and be attentive to tasks. Since people with schizophrenia have a very hard time focusing on tasks, this default mode network became a target of study. A FAILURE to de-active the fault network activity has been associated with schizophrenia.

What are neurohormones?

substances released into the blood by neurons

How does the ANS coordinate multiple functions?

sympathetic + parasympathetic activation. Actopms are typically multiple, widespread, and relatively slow.

What determines LONG-term feeding behavior?

• Body weight is a controlled variable; it regulates feeding behavior in the long term through feedback mechanisms that measure body fat; often genetic factors will play a role in this

Do drugs of ABUSE trigger LTP?

➢ Ungless/Saal: drugs of abuse all cause LTP at glutaminergic synapses in the VTA ➢ Conrad: Ca-permeable AMPARs contribute to relapse

What is short-term feeding behavior?

• Short term feeding behavior is governed by physiological as well as hedonic factors (TASTE and SMELL)

What is the ENTERIC DIVISION?

➢ A part of the autonomic nervous system that functions INDEPENDENTLY of your nervous system; consists of two webs of neurons connected to each other ➢ Nervous system for your GUT; controls many of the physiological processes involved in the transport and digestion of food; operates with a great deal of independence

What do all drugs of abuse have in common?

➢ Although various drugs of abuse bind to different brain regions, they ALL BIND to the VTA-nucleus accumbens region ➢ The rest of binding sites are in different parts of the brain for different drugs; possible reason for different drug effects; only commonality is VTA-NA

What was LOEWI's experiment?

➢ Basically he stimulated vagus nerve of donor heart, and the heart rate slowed; he removed a fluid sample from this and placed it on recipient heart, and heart rate also slowed, showing that it was a chemical ➢ CONCLUSION: Vagus nerve stimulation releases a substance Loewi called Vagusstoff, which has the effect of slowing the heart rate; this substance was shown to be acetylcholine • The sympathetic transmitter is Norepinephrine

What happens 24 hours after treatment with any of four addictive drugs?

➢ COCAINE, NICOTINE, MORPHINE, ETHANOL; all caused potentiation of AMPA component; a single exposure cause LTP at glutamate neurons; if lots of synapses are potentiated, will be much stronger drive onto those neurons ➢ 24 hours after treatment with any of four addictive drugs, AMPAR/NMDAR ratio was increased ➢ Therefore, multiple drugs of abuse all cause LTP at VTA glu synapses • Cause LTP on dopaminergic neurons through glutaminergic synapse

What was the control of the effect of drug on LTP experiment?

➢ CONTROL: CNS acting drugs didnt cause LTP • Fluoxetine=Prozac; used to treat depression • Carbamazepine: used to treat bipolar disorder and epilepsy • Do NOT cause LTP and do not cause addiction; non-addictive drugs work on the brain, cross into the brain non-addictively

• What is the breakdown concerning the neural basis of four complex behaviors? How does this determine our perceptions of free will?

➢ Eating, Drinking, and Sleeping • Vasopressin, Serotonin ➢ Drug Addiction • Dopamine ➢ Mate Selection • Oxytocin • Vasopressin ➢ Stress and Aggression • Cortisol, Norepinephrine ➢ QUESTIONS perceptions concerning free will

What is an EEG?

➢ Electroencephalogram (EEG): have scalp electrodes (non-invasive); they pick up really tiny voltages; miniscule electrical signals; EEG measures active synaptic input; Brain activity: negative dip in scalp recording; EEG is the sum of many small signals; around active inputs, have more negative area, while relatively more positive where there is NO activity. Summation of signals yields giant dips (large amplitude + low frequency from synchronous activity). Small EEG signals imply desynchornized activity; summation of signal will yield scratchy, low amplitude and higher frequency changes in EEG

What experiment did they do on rats concerning the enteric division?

➢ Experiment: Rats LIKED sweet things, and DISLIKED sour things • They did a test where they had the rat eat sour things, but also infused glucose into its gut; they found that the GUT expresses similar SWEET taste receptors as the tongue • There was CONDITIONED acceptance and preference but NOT altered taste reactivity responses to bitter and sour flavors paired with intragastric glucose infusion • They drank a lot more of the substance that was associated with glucose; they don't "enjoy" either; still not liking what they are drinking (no particular preference in terms of reaction), but they do drink a lot more of the one getting SWEET infusions in stomach; it is interpreting flavor of liquid and altering behavior of animal; even though enteric nervous system is separate, there is an association going on

What neuroadaption occurs when addictive drug creates compulsion to seek it despite better judgment of user?

➢ Getting past withdrawal is not the same thing as recovering from addiction; instead the brain remains different, making the drug seem desirable or even essential

How does eating relate to SEROTONIN LEVELS?

➢ Measurements of serotonin in the hypothalamus rise during a meal, especially in response to carbohydrates ➢ This effect of carbs on mood is particularly evident during periods of STRESS, possibly explaining the food-seeking behavior and weight gain of stressed people ➢ Drugs that elevate serotonin levels in the brain are powerful appetite suppressants

What are river Dolphins? Indus River dolphins?

➢ RIVER dolphins: Dolphins that live in a very turbulent rocky world (DANGEROUS) rivers; Bottle-nosed dolphin; strategy they've adopted involves switching of hemispheres sleeping so it can survive and flutter and avoid getting hurt and go to surface periodically to get air; one of the sides is awake, one side asleep; switch off; half the brain sleeps at a time ➢ Indus river dolphins: don't sleep very long; micro-sleeps that are about 5 seconds long; do that throughout the whole day and yield large hours of sleep but in little snapshots

What induces drug relapse?

➢ Small dose of drug itself ➢ Environmental cues related to the drug or its use ➢ STRESS; if we stress the animals, they have a very large increase in response; tend to nose-poke for drug more often

What occurs during cocaine withdrawal?

➢ These authors found that NEW, Ca-permeable AMPA receptors are inserted during cocaine withdrawal; even stronger synaptic connection ➢ These receptors can be selectively blocked by the drug NASPM ➢ By day 45, amount of craving and desire to get cocaine goes up a great deal in this period; incubation of cocaine craving; when a person is able to separate from the drug, overtime they experienced this increased craving that doesn't wane, but rather seems to escalate

How did they measure whether drug abuse causes LTP?

➢ When LTP occurs, AMPA receptors fly into synapse and create potentiation of AMPA component, and NMDA component doesn't change (don't add more NMDA receptors); used levels of AMPA to NMDA receptors as measure of if LTP has occurred. Synapse might have certain number of AMPA and NMDA receptors before drug abuse with a certain amount of current going through each; drug abuse however may trigger LTP, which causes AMPA receptors to be inserted into the membrane, increasing the concentration of AMPA receptors and the amount of current flowing through AMPA receptors, while the current flowing through NMDA receptors will remain the same since the number of NMDA receptors is constant.

What happens when the lateral hypothalamus is lesioned? When stimulated?

➢ When the lateral hypothalamus is lesioned, the animal stopped eating ➢ Electrical stimulation of the lateral hypothalamus triggered feeding behavior

What is EEG interpretation?

➢Synchronized activity: large amplitude, low frequency; Characteristic of relaxed or sleeping brain ➢Desynchronized activity: LOW amplitude, high frequency; Characteristic of an active, awake brain

What is ocular dominance SHIFT?

➢When the patterns of activity from the two eyes is brought out of register, replacing the pattern of activity in one eye with random activity, the binocular connections in the striate cortex are profoundly disrupted *Neurons that normally have binocular receptive fields instead respond only to stimulation of the non-deprived eye; this change in the binocular organization of the cortex is OCULAR DOMINANCE SHIFT