Brain & Behavior SG
What is anarchic hand syndrome?
'Alien hand syndrome' (one hand acting autonomously as if having its own will)- rare condition associated with lesions of the dorso-medial frontal lobe and its callosal or intralobar connections. Affects contralateral hand
What is Prosopagnosia?
'Face blindness' The Fusiform Gyrus is located in the inferior part of the TEMPORAL lobe and has a region used in face identification (Fusiform Face Area) [Agnosia = 'not knowing']
What are the (+), (-) signs of schizo?
(+): hallucinations, delusions, disorg. speech, disorg or catatonic behavior (-): lack of motivation and apathy; cognitive impairment (cognitive impairment is the best predictor of long-term outcome). DSM-V definition for schizo (≥2 of the above positive symptoms for ≥6 months. (-) symptoms count as one)
What is the reduced neuropil hypothesis (WRT schizo)?
(neuropil = less total neuronal mass, but same #) Same number of neurons packed in tighter space= reduced cell size, less branching, reduced spine formation. Affects whole cortex.
Genetics of Major Depressive Disorder (MDD)?
- 1st ° relatives of depressed = 2-3x risk of MDD - Dizygotic concordance = 20% - Monozygotic concordance = 60%
What are the 3 key areas of the Hypothalamus involved with regulating appetite?
- Arcuate Nucleus: regulate metab, most leptin recep's, POMC & NPY neurons (which both project PVN and LHA). - Paraventricular Nucleus (PVN): Metabolic regulation. Projects to pituitary (TRH & CRH) and ANS. [Think Cushings/ cortsteroid weight gain] - Lateral Hypothalamic Area (LHA) = Lateral n. of hyp.: Food-seeking behavior, project to cerebral cortex, stim ^ appet and lesion dec appet.
Big Picture of Appetite, related hormones, and brain areas involved.
- Cholecystokinin = satiety marker - Ghrelin = ^hunger, stims NPY in arcuate nucleus (inhibits POMC) - Leptin = from adipose, stims POMC, inhibits NPY - POMC = arcuate nucleus, reduce appet., ^ energy expend., produce α-MSH. Stimulants ^. - NPY = arcuate nucleus, decrease appet. and energy exp., inhibit POMC via GABA, produce AGRP, stim'd by ghrelin, inhibited by leptin - α-MSH = MCR4 agonist > suppress hunger - AGRP = antagonizes MCR4 > increase hunger
What is the interplay between GABA & Glutamate?
- GABA neurons have NMDA receptors - Less NMDA -> less GABA released - Inhibit NMDA, -> increase pyramidal cell activity and Glutamate release because the GABA interneuron no longer inhibits the pyramidal cell from releasing Glutamate
What is immediate memory, example
- Holding short facts, eg repeating a phone #. - Digit span test - Disruptable
Treatments of Schizophrenia
- In general, 60% DRD2 occupancy = effective (potency WRT at dopamine receptor) - High-Potency • Haloperidol 5-10mg/d • Fluphenazine 5-10mg/d - Mid-potency • Perphenazine 20-40 mg/d - Low Potency • Chlorpromazine 200- 400mg/d
What role might Serotonin play in Schizo?
- LSD activates 5-HT2A (receptor) - Clozapine works by blocking 5-HT2A [So there is some evidence that 5HT is doing something]
What are the biological effects of pups raised by mothers who provide lots of attention (via licking and grooming)?
- Low corticosterone secretion. - Less CRH-mRNA produced in hypoth - More glucocorticoid receptors because of less methylation on the DNA (less methylation on GR promoter gene). - Increased willingness to explore a novel environment. - ^licking/grooming seen in next generation d/t epigenetics
What are the neurotransmitter symptoms implicated in major depression?
- Low trp, 5HT, and 5HIAA (metab. of 5HT) in suicide pts. - Decrsd 5HT2a receptors in depressed. - Polymorphisms of 5HT1a R's w/ less 5HT affinity. - Δ's in CSF dopamine-β-hydroxylase - NE and Dop low in depression= basis of TCA's, SNRI, DOPergic meds. - Glutamate: sub/cortical glu concentrations low in dep'd= use ketamine/ riluzole
Frontal Cognitive Syndromes
- Memory deficits/impaired abstract thinking and inhibition - Dysexecutive symptoms (switching hand slap test) - Affective-aprosodia (lateralized to the right, can't detect inflection in voice etc.) - Neglect (lateralized to the left) - Apraxia (ideomotor or limb kinetic) - lateralized to the left - Broca's aphasia - lateralized to the left
What role might Glutamate play in schizo?
- NMDA antagonists mimic (+) and (-) sx of schizo - Differences in auditory ctx of schizos is a result of NMDA ->Don't give NMDA agonists though because of seizures [NMDA is a Glutamate receptor and ion channel of neurons]
What are 3 theories explaining the neurobiology of depression?
- Neurotransmitters: Monoamines NE, Dop, 5HT - Neurogenesis/Neurotrophic: NGF, FGF, BDNF low - Neuroendocrine (HPA axis): Cortisol damages Hippocampus which is HPA brake. Also decrease BDNF - Neuroinflammation: ^ of cytokines IL-2, IL-6, TNF-α, and IFN. Pts with high CRP. - Circadian Rhythms: 80% MDD ppl have probs with sleep. Less slow wave sleep. - Evolutionary: way to stop negative behavior, or reduce distracting stimuli= anhedonia; optimism bias
What are the tracts involved with pain?
- Spinothalamic tract: • Signal travels to thalamus and cortex • Provides awareness of location of pain "where does it hurt?" • Pain Asymbolia (lack emotion of pain) - because some emotional aspects involved in this tract - Spinoreticular (spine to retic. form. of pons to thalamus) and spinomesencephalic (spine to periaqud gray of midbrain) Tracts: • Communicate unpleasantness of sensation • "how much does it hurt?" • Activates emotional parts of brain - ACC, insula, amygdala, prefrontal ctx Some pain intolerance with greater activation of the cortical areas anterior cingulate cortex (ACC), insula cortex, and prefrontal cortex, along with the somatosensory cortex Low COMT activity assoc. w/ ^pain sensitivity. (COMT breaks down NE, E, and DA) Endogenous pain suppression from Paqdct gray (midbrn) -> nuc raphe-magnus -> spine AND ALSO Loc Coer (Pons) -> spine
What is the prevalence of Neuropsychiatric disorders WRT DALY and YLD? DALY = Disability Adjusted Life Year (years lost d/t dx) YLD = years lived with dx
- Suicide is in the top 10 causes of death (higher prevalence in neuropsych dx) - Neuropsych disorders responsible for 43% of all YLD's in North America and Europe (less infectious dx and malnutrition)
Symptoms clusters of depression and NT's implicated
-General Anxiety, obsessional thoughts Serotonin dysfunction -Anhedonia, psychomotor retardation, amotivation Dopamine dysfunction -Panic GABA dysfunction -Fatigue, co-morbid chronic pain Norepineprhine dysfunction (SNRI's, TCA's)
What three findings are consistent in autistic patients in social situations?
1. Avoidance of eyes*** 2. Focus on mouth 3. Preferential attention to objects rather than people
Environmental affects of schizo?
1. Maternal infection 2. Maternal starvation and famine (folate def? birth hypoxia) 3. Advanced paternal age (epigenetic, spont sperm mutat) *note - children at a genetic risk are more sensitive to environmental problems.
Theories of why we sleep
1. Neurogenesis in dentate hypo 2. Restoration to clean up daily damage 3. Memory consolidation
What are the areas and connections (white matter tracts) of the Parietal lobe?
1. Post-central gyrus 2. Superior parietal lobule (^sup prtl ctx activity in depress.) 3. Inferior parietal lobule 4. Precuneus (medial) (mindfulness = ^ activity in depress.) 5. Posterior parietal gyrus Posterior part of Arcuate fasciculus Cingulum (connects frontal lobe to posterior parts)
What are the main divisions of the Temporal lobe?
1. Primary auditory cortex: [ctx deafness for sounds (R) or words (L)] 2. Auditory association cortex: [Wernicke's, Anomic- or Conduction- aphasias, Receptive aprosodia - tone of what ppl say) 3. Visual association cortex: 4. Temporopolar cortex: Macropsia, Micropsia, Pelopsia, Teleopsia, autoscopy, Prosopagnosia, Alexia (Memory & Behavioral sx associated with amygdala and hippo which are in the temporal lobe, but functionally part of limbic system)
Neuroanatomy of Frontal Lobes:
1. Primary motor - most posterior 2. Premotor/SMA (supplementary motor area) - Helps w/ planning of motor 3. Broca's 4. Prefrontal a. Orbitofrontal (OFC -> vlCaud) [Disinhibition] b. Anterior Cingulate (ACC -> NuAcc) [Apathy] c. Dorsolateral (DLPFC -> dlCaud) [Executive dysfxn] Frontal-Subcortical Circuits Shared Anatomy: Frontal Cortex (OFC, ACC, DLPFC) -> Striatum (vlCaud, NuAcc, dlCaud) -> GlbPall/SbNig -> Thalamus (thalamocortical projections -> back to Frontal Ctx)
What are the 5 known large-scale neuronal networks?
1. Right hemisphere dominant spatial attention network: epicenters in dorsal posterior parietal cortex, the frontal eye fields, connected by white matter tract cingulate gyrus 2. Left hemisphere-dominant language network: epicenters in Wernicke's and Broca's area (connected by arcuate fasciculus) 3. Memory-emotion network: epicenters in the hippocampo-entorhinal regions and the amygdaloid complex 4. Executive function comportment network: epicenters in the lateral prefrontal cortex, orbitofrontal cortex, and posterior parietal cortex (connected by Superior longtiduinal fasciculus) 5. Face-and-object identification network: epicenters in lateral temporal and temporopolar cortices (and 1° visual cortex Br 17) (connected by inferior frontal occipital fasciculus)
What are the two factors that create psychopathy (antisocial behavior)?
1. impulsive aggression 2. emotional shallowness *associated with low resting heart rate, hypofunctioning amygdala (possibly) and increased NAc function. Less orbitofrontal activation in response to choosing to cooperate.
How does caloric restriction aid in protecting the brain [WRT AlzhD]?
1. limited oxidative stress 2. reduces DNA damage 3. Increases BDNF production [BDNF = Brain Derived Neurotrophic Factor]
Prevalence of Narcolepsy and what happens
1:2000; flawless transition between sleep stages are gone and you go from awake to sleep right away. See excessive daytime sleepiness.
What happens during Long Term Potentiation
2 neurons give rapid signals, resulting in greater stimulus in post-syn. neuron. When normal activity resumes, increased activity in NMDA induces gene expression. Gene expression results in structural changes on the neuron and spine formation
When does the first episode of REM occur?
90 minutes after sleep. Decreased in patients who are exhausted.
What are emotions?
A response to stimuli. Emotions, motives, and desires are types of feedback mechanisms to guide transition from current state to goal state.
Why is the amyloid plaque a reasonable hypothesis to Alzheimer's?
A-beta is toxic to neurons. People with early onset AD have increased levels of A-beta. A-beta can seed progression of the disease. We don't know if it is too much APP (Amyloid Precursor Protein) or a failure to clean up APP that causes AD.
What is the Anterior Cingulate Cortex (ACC) Circuit? What type of behavior seen with lesion?
ACC circuit = 1 of the frontostriatal circuits Part of the mesiofrontal lobe that just bounds the corpus callosum. ACC ctx -> Nuc Accumbens -> GlobPall/ SubsNig -> Thalamus (back to ACC ctx) Lesion: - *APATHY* (loss of volitional will) - Abulia - Extreme = akinetic mutism (no eating unless you spoon feed) - Loss of spontaneity - Lower extrem paresis
What is the correlation between ADH and aggression?
ADH increases aggression. ADH Receptor blockers decreases aggression.
What is beta stage
AWAKE and >12Hz
Frontal Abulic, Behavioral, and other Syndromes [Abulia = lack of will/motivation]
Abulic: - Blunt affect, reduced interests - Lack of motivation, reduced concentration - Limb akinesia, mutism Behavioral: - Personality changes, imitation and utilization behavior, grasping, emotional lability, disinhibition (eg frontotemporal dementia = previously nice old person becomes a dick) Other frontal-related syndromes: Schizo, autism, stuttering
What are the following: Acalculia, Alexia, Agraphia?
Acalculia - loss of the ability to calculate or understand quantity Alexia - loss of the ability to read Agraphia - loss of the ability to write [Parietal Symbolic Thought/Memory Syndromes]
What is the function of the amygdala in pleasure-seeking?
Acquires and retains lasting memories of emotional experiences, whether pleasureable and traumatic.
What defines REM sleep?
Activity very similar to awake stage.
How do we know genetics is important WRT intelligence?
Adopted children have cognitive skills that match biological parents and have almost 0 correlation with adoptive parents
What are the amyloid plaques in AlzhD? How are they formed?
Aggregates of Amyloid-beta proteins that are cleaved from Amyloid-beta precursor protein by beta secretase and gamma secretase. The clumping of filaments forms the plaques.
What happens at the gray matter in children with ADHD?
All have less gray matter as children, all experience normal pruning during adolescence. Children who remained impaired had more thinning at mPFR at beginning of study. Children who grew out of the disorder had normal gray matter thickness in right parietal cortex. Parietal cortex may be compensatory.
What defines the awake stage?
Alpha activity, 8-12 Hz
What POMC neuron enhances female libido
Alpha-MSH activated in POA.
What is the most common cause of dementia?
Alzheimer's Disease (AD) (Reduced hippocampal glucose metab. predicts AD. Women generally show decline in hippocampal glucose metabolism with age)
What are the best-known performance enhancers?
Amphetamines and methylphenidate- they are agents that improve alertness and then improve cognitive performance.
People who have anticipatory anxiety have greater activation where?
Amygdala and hippocampus and insula.
What is dyslexia?
An unexpected difficulty in reading in a person with otherwise normal intelligence and motivation
Why does anisomycin inhibit long term memory formation?
Anisomycin inhibits protein synthesis, thereby inhibiting long term memory because it requires protein! Normal steps of "Long-Term Potentiation" for learning: 1. Glutamate (excitatory neurotransmitter) ontp AMPA -> 2. NMDA receptor opening -> 3. Signal to nucleus -> 4. Gene expression induced -> 5. Protein synthesis -> 6. Structural changes like spine formation (Consolidation) (Anisomycin messes up step 5)
How would frontal motor injury result in an eye gaze abnormality?
Anterior to the primary motor cortex at the junction between the precentral gyrus and the superior frontal sulcus, is the frontal eye field • Lesions to the frontal eye field and its connections manifest with gaze abnormalities
What produces an increase in dopamine at the NAc (Nucleus Accumbens)?
Any enjoyable behavior!
Where is the largest concentration of leptin receptors
Arcuate Nucleus of hypo. POMC and NPY modulate the leptin signal
What is Gerstmann's syndrome?
Associated with a left parietal lesion manifesting with finger agnosia (loss of ability to recognize a stimulus), left/right disorientation, acalculia, and pure agraphia [• The inferior parietal lobule and posterior parietal gyrus are connected to visual areas of the temporal and occipital lobes through U-shaped fibers. • Damage to these cross-modal transition zones can produce defects in the ability to integrate memory, vision and proprioception]
REM
Awake mind, paralyzed body, usually 5 episodes nightly.
What is the Gate Theory of Pain?
Aβ fibers can dampen the pain signal of the C-fiber • A signal from the larger mechanoreceptor activates an inhibitory interneuron in the dorsal horn • Results in a smaller signal conveyed to the brain. • Rationale for the use of transcutaneous electrical stimulation (TENS) (Aβ fibers "gate" the pain neuron through an inhibitory interneuron)
How does BDNF affect anxiety?
BDNF INCREASES anxiety when at NAc. Antidepressants may decrease BDNF at NAc. (But antidepressants may increase BDNF at the Ventromedial n. of hyp. which is the satiety center. BDNF and VMN of hyp. = sated).
What role does the basal forebrain have in memory
Basal forebrain produces Ach, a neurotransmitter that is necessary for memory and damaged in Alzheimer's. (Therefore cholinergic drugs inhibit cholinesterase - prevent breakdown of Ach). NOTE: Protein synthesis and Long Term Potentiation required for learning.
What brain structure is generally associated with OCD?
Basal ganglia, OFC, ACC. Circuit of OCD does depend on the task at hand. (Amygdala NOT involved) Dopamine (DA) agonists can exacerbate OCD and vice versa, therefore dx's where DA is key NT have high co-morbidity of OCD: Huntington's, Tourette's, Parkinson's, Sydenham's chorea, PANDAS
What are some Frontal Lobe Testing methods?
Bedside testing: - Alternative sequencing: go/no go, or Luria's fist-edge-palm - Tests of abstraction - Lexical fluency Wisconsin Card Sorting Test: - Sort cards by color, shape, number, etc. then change the sorting method. Perseveration? Trail Making Test: - Trail line from number to letter with alternating directions (part of Montreal Cognitive Testing) Stroop Test: - "Red" word (in green font) (tests executive functioning and inhibition)
What EEG pattern is associated with alert and awake?
Beta- rhythm- awake and alert. If you increase neurofeedback, you can increase beta- waves!
What causes memory loss?
Bilateral medial diencephalic lesions (MEDIODORSAL n. of THALAMUS = memory loss = Wernicke-Korsakoff syndrome), basal forebrain lesions, korsakoff's or thiamine deficiency.... ALL Visible on Imaging. Seizures, ECT, concussions, ischemia, cerebral anoxia, and transient global amnesia cause memory loss that CAN'T be visualized on imaging.
What is the energy homeostasis? What regulates it primarily?
Body's metabolic "set point," regulated by genetic factors mostly.
How are autistic patients brain size affected?
Brain size is initially reduced, drastically increases first year of life (less pruning), then returns to normal during adulthood (Synaptic Dysregulation appears to be underlying problem in Autism)
What do we know about attention and external stimuli?
Brain's ability to attend to stimuli as more are added is finite. Capacity to ignore extraneous stimuli is integral to successful adaptation. (Bottom-up modulation from ARAS = grizzly bear in room. Top-down modulation from prefrontal, parietal, limbic cortices = reading book, goal-oriented behavior, etc.)
Expression of what two transcription factors results in protein synthesis in addicted state?
CREB is activated because of increased dopamine con'c and dampens reward circuit. Delta-FosB does similar effect but stays for weeks and months in cells. [Side note: Protein phosphatases dephosphorylate CREB -> decrease gene expression = forgetting; inhibition enhances learning]
What is Capgras syndrome? What is Fregoli syndrome? What is Anton's syndrome?
Capgras syndrome - belief/experience that an identical appearing imposter replaces a familiar person Fregoli syndrome - in which unfamiliar people are perceived as familiar (typically as a person in disguise with malevolent intent) can be interpreted as a hyperconnection between visual, emotional and memory networks Anton's syndrome - Cortical blindness, but person thinks they can still see (confabulation) [Capgras & Fregoli = Reduplicative phenomena disorders - Can be associated with lesions to the inferior longitudinal fasciculus and inferior fronto-occipit fasc.]
What is Balint syndrome? What causes it?
Caused by bilateral lesions of the parietal-occipital cortex and is characterized by simultagnosia (the inability to perceive simultaneous stimuli), optic ataxia, and oculomotor apraxia, is due to bilateral degeneration of the parieto-occipital cortex [• The inferior parietal lobule and posterior parietal gyrus are connected to visual areas of the temporal and occipital lobes through U-shaped fibers. • Damage to these cross-modal transition zones can produce defects in the ability to integrate memory, vision and proprioception]
Peripheral nociceptors: (for pattern recognition)
Channels TRP & GPCR's: - TRP: Transient Receptor Potential, eg TRPV1 for capsaicin or acid or heat and increase NA+ and Ca2+ in cell. - GPCR: G-prot coup recep: eg BK2 for bradykinin but other GPCR's for Eicosanoids, Purine nucleoside P2Y, 5HT1, 5HT2a, GABAb, adrenergic, somatostatin, NPY, opioid receptors. Ligand-gated ion channels: - ATP gated P2X3, Nav channels, TRP, etc.
What is Kluver-Bucy syndrome?
Characterized by abnormal emotional placidity (i.e., absence of reaction), hyperorality (i.e., strong oral tendency in examining objects), hypermetamorphosis (i.e., tendency to attend and react to visual stimuli), altered dietary preferences, increased sexual activity and visual agnosia. [Orbitofrontal-Amygdala syndrome (Limbic Lobe)]
What is the finding associated with heart rate and aggressive behavior?
Childhood low resting heart rate is correlated with aggression in children.
How does HPA affect feeding?
Childhood stress is associated with increased weight problems in adolescence and adulthood. CRH and Cortisol stimulate dopamine release at NAc (harder to resist cravings). GC's increase fat deposit. Stressed rats given sweet water have lower GC levels.
Who is most at risk for schizophrenia?
Children at a genetic risk are more sensitive to environmental problems.
What retuicular activating system neuron is active in wakefulness and REM?
Cholinergic neurons
How does the reticular activating system affect sleep?
Cholinergic neurons activate thalamic relay neurons. Also NE neurons (LC), 5HT (Raphe Nuclei), dopamine (PAG) are all active during arousal.
What is the process of transferring short term to long term
Consiolidation Sensory cortices -> Parahippocampal gyrus -> Hippocampus -> Cortex Information moves to different cortical layers with time. Happens during sleep.
What test can you use to test attention? What age level has the best attention?
Cotinuous performance tests- adults have the best attention
From a behavioral point of view, the cerebral hemispheres can be divided into four major components: primary sensory cortex, primary motor cortex, association cortex, and limbic-paralimbic cortex. (Click over for pic of Idiotypic, homotypic, limbic areas, paralimbic areas, etc.)
Cytoarchetectonics also shows more diffuse arrangement of neurons in heteromotor areas (eg parietal) vs specific like V1
How does dopamine affect the internal clock?
D2 agonists accelerate internal clock, D2 antagonists inhibit the internal clock.
Increase of what catecholamines at the PFC increase working memory and improve attention?
DA and NE enhance working memory and improve attention. (there is a 'sweet spot' amount of Dopamine/NE). Important in Top-down modulation form of attention (prefrontal, parietal, limbic cortices)
What is the Dorsolateral Prefrontal Cortex (DLPFC) Circuit? What type of behavior seen with lesion?
DLPFC circuit = 1 of the frontostriatal circuits DLPFC ctx -> DrslLat Caudate -> GlobPall/ SubsNig -> Thalamus (back to DLPFC ctx) Lesion: - *EXECUTIVE DYSFUNCTION* (planning, sustaining, monitoring of complex behaviors) - Appear inattentive, undermotivated - Perseveration - Stimulus-bound behavior - Diminished verbal fluency
When learning about facts or historic events, what type of memory is that?
Declarative/Explicit Conscious (declarative includes facts, concepts (semantic) and Events, experiences (episodic)/ long-term memories. *HIPPOCAMPUS) This memory gone in patient H.M. -> "Memento". Temporal lobes gone in H.M.
What changes does chronic alcoholism have on the brain
Decrease in total brain volume, especially gray matter. (Physio side note: alcoholic ataxia = truncal ataxia = Purkinje cell damage in Vermis/ paravermal regions)
How does chronic sleep deprivation affect people?
Decreases behavioral alertness and decreases working memory
What does castration in males do to mounting behavior?
Decreases mounting behavior, but can be reinstated with testosterone.
How do Delay Neurons work?
Delay neurons= fire at start of cue, end with response. If distracted, no delay neurons function. Delay neurons are more common than cue neurons and cluster together.
Examples of lesions resulting in attention problems:
Delirium encephalopathy: ARAS involved Hemineglect: Higher order spatial information, posterior parietal lobes, superior colliculus, anterior cingulate cortex Balint's Syndrome: bilat parieto-occipit lesions: Triad: Simultagnosia, Optic Ataxia, Oculomotor Apraxia - from watershed infarcts, open head injury, posterior cortical atrophy
What defines stage ¾ sleep?
Delta wave sleep, deep sleep (<5Hz)
What is a well-known cause of cognitive impairment?
Deprivation in early infancy. There is a dose-response relationship between IQ and yrs. spent impoverished.
What is habituation?
Description of how novel stimulus will stimulate good feelings but a repeat stimulus will not release as much dopamine.
How does eating resemble addiction?
Destruction of forebrain dopamine system leads to decreased free feeding. Reduced D2 receptors in striatum of obese individuals, similar to addicted people. Activation of OFC associated with food cravings. Food ^ Dop. in ventral striatum -> endorphins. NucAc sends dop. projections to hypo. [Contrave = new obese drug (naltrexone & bupropion combo) Buproprion is dopaminergic which can stim POMC via α-MSH. POMC also makes β-endorph which is autoreg inhibition... so... Naltrexone is antag. MOP-R. which prevents the autoreg. inhibit.]
White matter changes in schizo pts?
Disrupted integrity of white matter, reduced myelin seen with DTI (Diffusion Tensor Imaging)
What is Optic ataxia?
Disturbance of limb guidance such that patients are unable to reach for objects in an otherwise intact visual field
Winners and losers have different growth factors in SVZ (subventricular zone). What are they?
Dominant = BDNF Subordinates = NGF
What is the difference in dopamine between dominant and subordinate monkeys?
Dominant monkeys have more D2 receptors in the striatum. Hence less of a pleasureable experience will stimulate "good feelings" (SIDE NOTE: ventral striatum = NAcc & olfactory tubercle, while dorsal striatum = caudate & putamen)
What is the primary NT in reward system
Dopamine
What pleasure areas of the brain are active in mothers when seeing their offspring?
Dopamine activates Orbitofrontal cortex. Increased dopamine release at nucleus accumbens. [Dopamine blockers impair maternal behavior - schizo]
Dopamine and aggression?
Dopamine increases in the NAc in aggressive rats.
What is Akinetopsia?
Dorsal stream lesions causing selective loss of motion vision
Which area of the prefrontal cortex subserves executive function, i.e. planning and sustaining complex behaviors?
Dorsolateral prefrontal cortex
What site of the brain integrates sleep signals?
Dorsomedial nucleus of the hypothalamus. It projects to the VLPO from the SCN, allowing other things than light to affect sleepiness.
What hormones influence maternal behavior right before birth?
Drop in progesterone and rise in estrogen and prolactin before delivery. After delivery, maternal behavior is permanent (changes in preoptic area).
What defines stage one sleep?
Drowsy period, theta waves, 5-8 Hz
Global aphasia
EVERYTHING IS WRONG. Large, left perisylvian lesion.
How does CB1 Receptor modulate food intake?
Endocannabinoid Receptor- enhances motivation to seen and comsume palatable food. Stimulates food comsumption in hypo. Endocann. (2AG and anandamide) are also opioid-independent pain suppression
What are the most common physical brain findings of schizo pts?
Enlarged ventricles with subtle decreases in total brain volume and total gray matter. Usually gray matter decrease occurs with adolescence when pruning, apoptosis, synaptogenesis are occurring. - Shrinking of insula, thalamus, and ACC - Decreased prefrontal brain function, attention, memory, exec functioning - No ^in blood flow in Wisconsin card sorting test
What is AlzhD's normal progression?
Entorhinal cortex to temporal and frontal cortex to entire brain!
Does biology or environment determine the genetic makeup of offspring WRT attachment/licking grooming behavior?
Environment!
How does estradiol affect nerve volume, dendritic length, spine density and synaptic connectivity?
Estradio-exposed neurons had 22% more spines than control. NMDA R increased by 30%
What confers neuroprotection?
Estrogen
The preoptic area is rich in receptors for hormones that correlate to maternal behavior. What hormones?
Estrogen, Progesterone, Prolactin, and Oxytocin
How do steroid hormones interact with growth factors
Evidence thus far shows synergism.
What is a physical finding in Mentally Retarded children
Extensive dendritic spine abnormalities.
How do men and women navigate spatially?
F: Use landmarks M: Use spatial cues Side note: VMPFC involved in decision making (and processing risk and fear, and inhibition of emotional responses). Lateralization seen in sexes. F: may use more analytic, verbally-mediated strategy M: may use more holistic, gestalt-type strategy
What is Prosopometamorphopsia?
Face hallucinations and illusions characterized by distorted facial features. Likely to relate to a region specialized for face features on the lateral convexity of the occipital lobe
What is extinction WRT sensory input?
Failure to detect the stimulus on one side of the body when touched simultaneously on both sides
What are some signs that someone might develop AlzhD?
Faster than normal atrophy, decrease in energy metaboism (reduced glucose metabolism, volume loss of brain.
What happens if you stimulate the amygdala? Damage it?
Fearful behavior, freezing, and tachycardia. If you damage it- impaired fear conditioning. Amygdala is active during fear learning. - Central nucleus of Amygdala: receives projections from thalamic areas next to audit. part of thalamus: lesions prevent ^hr and freezing. (phasic fear) - Lateral nucleus of Amygdala: inputs from auditory thalamus: lesions affect classical fear conditioning [lateral projects to basal/basolateral which projects to central nucleus] Lateral nucleus is sensory interface, Central nucleus controls the responses Auditory cortex not required for fear conditioning
When looking at female hamsters exposed to testosterone in utero, how is their lordosis (mounting behavior) affected?
Females exposed to testosterone in utero do not exhibit lordosis (mounting behavior) when given estrogen and progesterone. Brain alteration prevents females from responding to female hormones.
What is congenital adrenal hyperplasia?
Fetuses are exposed to excessive androgens due to overactive fetal adrenals. (but don't produce cortisol). Females are born with masculinized external genitalia. More rough and tumble play. Enhanced spatial. Prefer other females.
What puts people at the greatest risk for mood disorders?
Fluctuating estrogen levels! (~5x more likely to become depressed during menopause)
What area of the brain may be indicated in cognitive impairment? (WRT schizo)
Frontal cortex, mainly prefrontal cortex.
What are the frontal lobe subdivisions and the fasciculi associated with the frontal lobe?
Frontal lobe = >1/3 cortical surface area
Where do normal readers have activity but dyslexic people don't?
Frontal region and temporal/occipital region (Phonics- activates same regions in dyslexics as fluent readers)
How does GABA affect anxiety?
GABA- calms down the brain. Ethanol, barbituates, benzodiazepines bind to GABA-R. Alterations in structure of benzodiazopene GABA-R may predispose people to anxiety.
What is the theory behind vaccinations for AlzhD?
Get the immune system to attack the amyloid plaques without attacking other parts of the brain. Goal: Inject A-beta peripherally so they are ingested by APC's, then presented to T cells, then activate B cells. Studies have suggested positive results but with some bad side-effects.
How does red wine help with brain function [WRT AlzhD]?
Gives superior brain function and less beta-amyloid.
What are some of the short-term signals of hunger? Long term signals?
Glucose mediates satiety. Mechanoreceptors send signal via vagus to hindbrain to transmit signal about gastric distension. Gut Hormones CCK- inhibits food uptake by inhibiting gastric emptying and stimulatig vagus. Ghrelin stimulates hunger Long term signal = Leptin produced in fat cells. ^conc'n of Leptin receptors in Arcuate Nuc of hypothalamus. POMC (brake) and NPY modulate the leptin signal. (physio side note: - Dorsomedial n. of hypoth.: stimulations results in obesity and savage behavior. Also integrates sleep signals from (aff.) SCN to (eff.) VLPO which allows sleeping in daytime. - Ventromedial n. of hypoth.: satiety center. Destruction results in obesity and savage behavior. Also center for female sex havior - Lateral n. of hypoth.: stimulation induces eating, destruction results in starvation
What is the basis of extinction?
Gradual reduction in response to a feared stimulus in response to repeated encounters. Effective tx for anxiety.
Why is an adolescent more prone to addiction?
Greater activity in NAc (accelerator)when winning and less activity in amygdala (the brake) when losing
How does mastery and cortical structure relate?
Greater the mastery of the skill, the greater the number of newly developed neurons that survived. Neurogenesis can happen in adulthood: Dentate gyrus of hippocampus, Subventricular zone, Olfactory bulb. Antidepressants can increase hippocampal neurogenesis.
What are the physical signs of Alzheimer's?
Gross atrophy of the cortex without localized foci due to neuronal cell death. Sclerotic plaques in the upper layers and tangles inside neurons.
What area of the brain is necessary for consolidation of long term memories
HIPPOCAMPUS!
What is common with highly creative people
High IQ and low latent inhibition.
What role does epigenetics play in memory?
Histone acetylation = incresed gene expression and protein = ^dendritic spine density, synapses, synaptic plasticity, memory Inhibition of acetylation has the opposite effect. (TL;DR Histone acetylation better for memory)
What are the following: hypoesthesia, hyperesthesia, dysesthesia, polyesthesia, agraphesthesia, and Atopesthesia? What is pain symbolia? What is Allodynia?
Hypoesthesia - reduced sensation Hyperesthesia - increased sensation Dysesthesia - when more than one modality is altered (either reduced or increased), the patient reports multiple symptoms such as tingling, burning, numbness, feeling of pins and needles Polyesthesia - when a single tactile stimulus is reported as several Agraphesthesia - impaired recognition of tactile letters Atopesthesia - inability to localize sensory stimuli Pain asymbolia - emotional indifference to pain Allodynia - innocuous stimuli activate nociceptors
PTSD and intelligence relationship?
IQ and PTSD are inversely related. Small hippocampus may also be risk factor.
NREM
Idle mind, paralyzed body.
What does testosterone do to the brain?
If present at critical periods, it both masculinizes and defeminizes the brain.
What is apraxia?
Impaired ability to execute or carry out learned purposeful movements (eg ideomotor apraxia- brush teeth) [There are also limb kinetic and constructional apraxias] May be seen in damage to anterior segment of arcuate fasciculus (in frontal lobe).- eg ipsilateral arm and face movement from the fasciculus damage, but contralateral hemiparesis. MORE LIKELY: damage to the supplementary motor area, premotor cortex, or posterior parietal cortex (left side).
What is implicit versus explicit emotion?
Implicit: Processes are autonomic Explicit: Conscious emotional feeling at different levels of consciousness.
What can prevent relapse in addicts?
Inactivation of PFC, Glutamate receptor blockade at NAc, increased glutamate in NAc.
What hormones increase with anxiety? Decrease?
Increase: Cortisol, Epinephrine, GH Decrease: Testosterone
What causes female vole bond formation?
Increased Oxytocin Improves +communication, ^trusting behavior, more +response of fathers and toddlers, enhances emotional recognition and responsiveness to others. Decreases social anxiety. May dampen Amyg/Cing circuit (active in fearful circumstances)
What is commonly seen in PTSD patients?
Increased activity in amygala, decreased activity in mPFC (no brake to turn off fear). Hippocampus reduced in size, and trauma! Small hippocampus is generally genetic!
What can cause motion hallucinations?
Increased activity in the dorsal occipital regions
How does ovariectomy influence brain function?
Increased risk for dementia and alzheimer's (AD). Reduced when taking HT. Women tend to be dx with AD later because sex modifies the relationship between the clinical presentation of SD and imaging markers of neuronal dysfxn.
What causes male vole bond formation?
Increased vasopressin (ADH) receptors in ventral pallidum (in basal ganglia) In humans, variations of vasopressin receptor 1a gene (334 allele = worse bonding) Vasopressin ^prosocial behavior, particularly in males Arginine Vasopressin Receptor (AVPR1) promoter region repeat length associated with altruistic behavior
What is the papez circuit
Info goes from ant. Nucleus of hypo to cingulated gyrus to hippocampus (subiculum) to the mamillary bodies via fornix to the ant nucleus via mammilothalamic tract.
What is the fear fast track?
Information goes from the thalamus to the amygdala before being interpreted by the cortex. This helps you react quickly to a threat but can cause a false alarm. Slower route = Thalamus -> sensory cortex -> Amygdala (cortex for processing how you should feel about the stimulus)
What does ECT do to memory?
Inhibits consolidation, erases recent long-term memory, causes some memories to be lost. Cognition ~ ^ after 6 months (BL worse than RUL) ECT = neuromodulation 50-80% response rate in major depression. RUL, ultrabrief pulse width best.
Which thalamic nuclei provides a critical relay for both attention and arousal?
Intralaminar (both attention and arousal important for multiple domains of cognition)
How does Oxytocin affect the Amygdala in men? In women?
Intranasal oxytocin in: - Men: dampens amygdala activity: decreases emotional face processing - Women: increases amygdala activity
How does learning affect cortical structure?
It increases branching and synapse formation. These changes can be blocked with NMDA antagonist. Note: NMDA is a Glutamate receptor.
What does the frontoparietal lobe do for intelligence?
It is enlisted when solving difficult problems
Anomic Aphasia
Just have problems naming things-‐ left angular gyrus
Aphemia
Just motor verbal output problem (ability to speak is lost) (usually means they can still write, therefore different than Broca's aphasia)
What are the long-term signals of hunger?
LEPTIN produced in fat cells. Its concentration correlates to total fat load.
What did Seigel discover about areas of the amygdala and aggression?
Lat and central groups facilitate predatory attacks, suppress defensive rage. Pedial aspect of basal complex has opposite effect.
What is latent inhibition and what is its association with creativity?
Latent inhibition is an animal's unconscious capacity to screen out and ignore irrelevant stimuli. This is reduced with increased creativity.
When activated, what area of the hypothalamus provokes predatory aggression?
Lateral hypothalamus. Also involves stealthy movement, premeditation, calm sns tone, hunting
Where do most people have majority of language lateralization?
Left Side *indicators: - Tachistoscopic (visual) and Dichotic (auditory) stimuli. - Split-brain (Corpus Call) pts. - Sodium amytal (Wada test) shuts down a hemisphere - (transcranial magnetic stim. used now). - Neuroimaging rCBF (regional Cerebral Blood Flow) fMRI, FDG- or SPECT- PET,
What layer of the brain does recent memory activate? Memory after 30 days?
Levels V and VI are activated by Fos with new memory. Levels II and III are activated by Fos with memories after 30 days.
What is androgen insensitivity syndrome?
Limited exposure to androgens. Genetically male (but sometimes female external genitalia) produce testosterone but don't recognize it. Look and act feminine, just infertile.
How does medial temporal amnesia usually occur?
Loss of temporal lobe or hippocampus.
What is Aprosodia?
Loss of the emotional and gestural components of language. Most likely resulting from damage to the right hemisphere of cerebral cortex (right temporal lobe - Right-sided Wernicke's equivalent)
What is aphasia
Loss or impairment of language caused by dysfxn in brain regions.
We have two types of groups when people are exposed to the same stressful stimulus. What are they?
Low responders- show anxiety at first then response decreases. High responders show higher, more persistent cortisol peaks.
What is Pseudothalamic syndrome?
Manifests with a combination of somatosensory loss, astereognosis (impaired 3D object tactile recognition), tactile extinction, hemiplegia (unilateral body paralysis), and focal sensory Epilepsy due to a parietal lesion
How do autistic patients differ from normal people WRT mirror neurons?
Marked decrease in activation of mirror neuronal network, esp. in frontal cortex. (pick up object = neurons firing. Same mirror neurons firing if seeing someone else do it. Seeing people suffering/ under threat can activate mirror neuron networks - ventral premotor & temporal parietal junction)
What happens if the preoptic area is damaged?
Maternal behavior disruption
When activated, what area of the hypothalamus provokes defensive aggression?
Medial hypothalamus, autonomic arousal, hissing and arching back, overt and reactive...
Who performs better with spatial orientation tasks?
Men
What psychological occurrence is sometimes associated with creativity?
Mental Illness- mainly depression and bipolar disorder. Worse periods are often associated with times of high creativity
Which part of the brain might be damaged with loss of volitional movement and apathy?
Mesiofrontal lobe (eg ACA territory infarct)
What is the Mesolimbic tract? Nigro-striatal? Mesocortical?
Mesolimbic Involved in motivational behavior: Originates at VTA (A10) -> innervates Ventral Striatum, Amygdala, Hippocampus. (in part related to addiction or psychosis or schizo) [NAc + olfactory tubercle = ventral striatum] Nigro-striatal involved in control of movement: SubstNigracomp (A9) -> innervates Dorsal Striatum Mesocortical involved in learning and memory: Originates at VTA (A10) -> innervates Frontal Cortex
What is short term memory
Minutes - eg locating lost keys - 4 words/5 mins (mean is 3 though) - Disruptable
5HT and aggression?
Monkeys with high rates of aggression have low CSF 5-HIAA (metabolite of 5HT). they engage in rough interaction that goes to unrestrained impulses. They are much more likely to engage in risky behavior.
How do cocaine and morphine affect dendritic spine growth?
Morphine reduces spine growth, amphetamines increase spine growth.
What determines abstinence?
Motivation to stay clean, but brain will never return to normal. Bonus pic on Drug Tolerance
What has been shown to cause faster extinction?
NMDA agonist (D-cycloserine) gives heightened response to postsynaptic nucleus. ERP (Exposure & Response Prevention) helps promote extinction for phobias etc. D-cycloserine helps promote this. [Long Term Depression in Cerebellar Cortex used for Procedural memory/ Classical conditioning]
Are antipsychotics a good tx for AlzhD?
NO! Most of them worsen the decline of AD when compared to placebo
How does NPY modulate appetite?
NPY neurons increase food intake and decrease energy expenditure. Produce agouti-related peptide (AGRP), an ANTAGONIST of MC4R (melanocortin receptor). NPY blocks POMC activity.
What is the differnce between NREM and REM dreams?
NREM- thought dreams, problem solving REM- bizarre dreams
Subcortical aphasia
Naming is poor and reading and writing is poor. Head of caudate and anterior limb of int. capsule
What growth factor, if given in the brain, could possibly help AlzhD?
Nerve Growth Factor (NGF)...prevents cholinergic degeneration
What different neurons modulate working memory?
Neurons are active during the cue while delay neurons are active during delay period.
Does habituation occur with cocaine?
No
Does dopamine play a role in schizo?
No, not really. It may diminish psychotic symptoms but it isn't the major problem. - BUT... (D2 Antagonists help, amphetamines worsen). Dopamine excites Pyramidal cell to release more Glutamate, but the NMDA receptor is messed up in schizos.
Skills like tying a shoe is what type of memory? (or receiving a shock/classical conditioning)
Nondeclarative/Implicit Unconscious (nondeclarative/procedural memories associated with carrying out certain performance. Associated with implicit memory/ *AMYGDALA) - This type of memory not lost in temporal lobe lesions - H.M. could learn to read inverted text, but not remember any content.
Does testosterone cause rage?
Nothing proven yet.
What is the Orbitofrontal Cortex (OFC) Circuit? What type of behavior seen with lesion?
OFC circuit = 1 of the frontostriatal circuits OFC ctx -> vntrlatrl Caudate -> GlobPall/ SubsNig -> Thalamus (back to OFC ctx) Lesion: - *DISINHIBITION* (Phineas) - Inappropriate affect (witzelsucht) - Acquired sociopathy (recognition of other people's emotion) - Aggression
Do NPY neurons inhibit POMC? Vice versa?
Only NPY neurons inhibit POMC neurons directly. POMC neurons do not inhibit NPY neurons. NPY ^food intake and decrease E expenditure. They produce agouti-related peptide (AGRP) which is an ANTAGONIST of the melanocortin receptor (MC4R) POMC (stimd by Leptin) -> α-MSH -> on MCR4, to reduce appetite.
Phineas Gage had TBI and resultant behavioral changes. Argumentative, stubborn, gambling more, drinking, belligerent, aggressive. How did brain injury do this?
Orbitofrontal - Ventromedial Prefrontal Cortex Arousal in body gives us a 'Somatic Marker' which helps us interpret what should be the next adaptive action. Indexed as Skin Conductance Response
What area of the brain plays a critical role in goal-directed behavior?
Orbitofrontal cortex
What is the association with orexin and sleep-wake
Orexin is active during wake. Pts with narcolepsy often have few orexin neurons in hypo.
What area of the brain has greater blood flow in creative people?
PFC has greater blood flow and is notably much higher in gray and white matter in humans than other mammals (High IQ and low latent inhibition also seen in creative people) [Latent inhibition = animal's unconscious capacity to screen out and ignore irrelevant stimuli]
What is the goal of POMC neurons? Output?
POMC neurons= BRAKE. They produce alpha-MSH which suppresses food intake. Effects are mediated through melanocortin receptors (MC3R and MC4R) in hypo. (MC4R = Melanocortin-4 Receptor = most common known single gene cause of obesity)
Oxytocin levels in which brain area increase maternal aggression?
PVN = paraventricular nucleus (Oxytocin & Vasopressin: Synthesized in Hypothalamus, released from post. pituitary to general circulation. Small neurons projecting from the hypoth to ant cingulate, NAc, and Amyg)
What problems with GABA interneurons do you see in schizo?
Parvalbumin GABA interneurons are reduced. mRNA for GAD (makes GABA) is decreased. - Decreased GAD67 (GAD1) and Reelin in schizos. - Dysregulated pyramidal firing in schizo affects working memory. - BUT... GABA agonists are NOT very effective antipsychotics
Urbach-Wiethe disease
Patient "SM" who felt no fear. Rare, autosomal recessive, bilateral calcification and atrophy of the the anterior-medial temporal lobes, particularly the AMYGDALA. Difficulty assessing un/familiar faces and FEAR. "close talker"
What were some of the effects of the Minnesota Starvation Experiment
Patients became obsessed with food.
What is Anton's syndrome?
Patients with cortical blindness due to extensive occipital lesions are sometimes unaware of their visual impairment
What is the association between reward and stimuli
People who can resist the impulse of reward and distraction and wait for the long term benefit generally tend to be more resilient, confident, and perform better on standardized exams.
Who does not show SCR (Skin Conductance Response)?
People with frontal lobe deficiencies failed to show SCR's. VMPFC lesion patients persist in selecting high loss (high reward) decks. = pathological gambling
What is the James Lange theory of emotion
Perceive emotion activates ANS which then feeds back to the brain and produces an experience of emotion.
What type of therapy helps dyslexic patients, even changing brain bio?
Phonics- activates same regions as fluent readers
What is the Pittsburgh Compound test?
Pittsburgh Compound-B binds to amyloid and can be visualized in a PET scan. May help identify pathology of AlzhD.
What happens during menstrual cycle for female schizophrenics?
Positive symptoms in women (hallucinations, delusions, disorganized language) REDUCE with rise in estrogen.
What area of the brain is associated with craving and obsession
Prefrontal Cortex, (DLPFC&OFC), activity in PFC correlates to "cravings"
Where do the VTA and NAc receive input from?
Prefrontal cortex, amygdala, and hippocampus (VTA & NAc = central structures of mesolimbic dopamine system)
What area of the brain is associated with working memory? How do you test its functioning?
Prefrontal cortex, test its functioning with the delayed-response task. Put food in front, cover it, then make monkey find it. Remember this is also where executive function resides.
Where does the ability to master difficult circumstances and maintain control reside?
Prefrontal cortex. Note mPFC (medial PreFrontal Cortex) and the anterior cingulated gyrus are connected to the amygdala. *mPFC applies brakes to the amygdala*
What are the brain regions implicated in major depression?
Prefrontal ctx and sup. parietal ctx. - Dec'd Hippocampal volume - Ant. Cingulate gray matter decrease - OFC gray decrease - White matter hyperintensities associated with LLD (late life dep) - Limbic hyperactivation (amy/fear), prefrontal deactivation (mood regulation) - "Default Mode Network" MORE active in MDD: medial prefrontal ctx, precuneus, sup. parietal ctx @ rest. = used in self-reflection.
Which area of the brain is larger in men than women?
Preoptic area of hypo, especially INAH 2 and INAH 3
What type of evidence is stored in the amygdala?
Primitive emotionally relevant memories. Amygdala can induce LTP and protein synth inhibitors prevent formation of fear conditioning.
What role does the neocortex play in memory?
Processes sensory info. Stores long term memory. Remote memories are stored throughout the cortex though. Long term memory storage: - Dorsolateral prefrontal cortex - Cingulate gyrus - Temporal lobe - Parietal lobe (side note about forgetting: Protein phosphatases dephosphorylate CREB -> decrease gene expression = forgetting; inhibition enhances learning
What is Paraphasia
Production of unintended syllables, words, or phrases
What brain changes do you need with learning?
Protein synthesis and long-‐term potentiation
What are neurofibrillary tangles?
Proteins on microtubules of the neuron. Damage to the MT causes the peripheral neuron to starve (b/c no transport). Tau proteins bind to the tangles to stabilize them. Phosphates attach to the tau proteins, causing them to detach and form tangles. [TL;DR: Hyperphosphorylation of tau proteins (microtubule-associated proteins) causing aggregation]
How are schizo and manic depressive disorders different?
Pt with schizo= persistent deteriorating course. Manic depressive= periods of remission. [schizo, bipolar, with psychotic features, and schizoaffective disorder share Same tx & have many of same research findings]
What does "g" or fluid intelligence represent?
Reasoning and novel problem-solving ability
Reelin- what is its function and relation to schizo?
Reelin is recognized by GABA interneurons. It is important for neuronal migration, axon branching and synaptogenesis. It is reduced in postmortem brains of schizo patients.
Retrograde v. Anterograde Amnesia?
Retrograde-‐ forget the past, unusual Anterograde, can't remember new events, most common. There is generally a period of retrograde amnesia in people who have not stored their memories yet.
How do growth factors change in people who are in passionate love?
Rise in NGF (Nerve Growth Factor)
What is the relay area of the brain
SCN (awake) to DMH to VLPO (sleep)
How does SCN modulate circadian rhythm?
SCN cell produces two proteins, CLOCK and BMAL1 that fuse together and activate transcription of CRY and PER. Those form a dimer that inhibits transcription of CLOCK and BMAL1. Buildup and breakdown takes around 24 hrs.
What changes did monkeys on calorie-restricted diet have [WRT AlzhD]?
Same APP (Amyloid Precursor Protein) but reduced A-beta (toxic to neurons). It enhances alpha-secretase, an enzyme that inhibits buildup of amyloid plaques.
What patients generally present with severe disconnect?
Schizophrenic and Autistic (ASD) patients -inability to understand other's feelings and establish reciprocal relationships. [Imitating facial expressions lights up the network and the emotional centers of the brain: insula, amygdala = empathy? -> defective in ASD]
What causes memory loss that can't be visualized?
Seizures, ECT, concussions, ischemia, cerebral anoxia, transient global amnesia
What is Achromatopsia?
Selective loss of color vision
Explicit Memory
Semantic and Episodic Memory (governed by hippocampus)
How sensory info gets processed
Sensory info goes to the cortex, then gets transferred to the hippocampus for consolidation, then gets put back into the cortex for long term storage
Implicit Memory
Skills, habits, and procedures (governed by amygdala)
What defines stage 2 sleep?
Sleep spindles, light sleep.
What is a common finding of brain size in children with ADHD?
Smaller total brain volumes- smaller gray AND white matter AND cerebellum.
What is Damasio's Somatic Marker Theory
Somatic Events are bodily sensations that link to a physiological experience. We listen to our gut responses.
Transcortical Sensory Aphasia
Speech and repetition are fluent but comprehension and naming and reading and writing are impaired. Damage to left supramarginal gyrus or left auditory cortex.
Wernicke's Aphasia has what problems?
Speech is fluent but comprehension is impaired. Repetition, naming, and R&W are all impaired. Damage to left posterior superior temporal lobe
For Broca's Aphasia, what do you expect to be damaged?
Speech is nonfluent and agrammatic but comprehension is intact. Impaired repetition, naming, R&W). Damage to left inferior posterior frontal lobe
Transcortical motor aphasia?
Speech is nonfluent. Comprehension, repetition and R&W are all intact. Speech is nonfluent and naming is poor. Damage superior and anterior to Broca's area - extrasylvian
What is conduction aphasia?
Speech, comprehension, Reading and writing are all intact but repetition and naming are impaired. Left supramarginal gyrus or left auditory cortex.
What is Speech? Language?
Speech- motor process involved in producing language Language- abstract symbols or representations that underlie verbal and written communication.
What spinal cord segment is larger in males than females? Why?
Spinal nucleus of the bulbocavernosus (SBN) because it is used for erection and copulation.
How does sleep change with age?
Stage 2- stays same, stage 3,4 decreases, awake time increases
How do stimulants influence the mesolimbic pathway? Opiods, alcohol and PCP?
Stimulants (nicotine, amphetamines) increase dopamine at NAc (Nucleus Accumbens). Depressants suppress inhibitory neurons that modulate NAc and VTA (Ventral Tegmental Area) [Pic shows changes in brain w/ ^use]
Why does stimulant addiction have a long-term effect on the brain?
Stimulants block dopamine reuptake, leading to decreased D2 receptors. Such a change persists 3-4 months after detoxification. This also explains the "withdrawal" effect
How do stimulants influence gratification?
Stimulants increase DA at NAc and have greater ease in blocking out irrelevant stimuli. It can focus attention on more favorable rewards
What is the Limbic-Hypothalamic Pituitary Adrenal Axis (HPA axis)?
Stress Stimulation (initiated by Amygdala) • Paraventricular nucleus (PVN) of the hypothalamus neurons release corticotropin releasing hormone/factor (CRH/CRF) • Anterior Pituitary secretes adrenocorticotropic hormone (ACTH) • Adrenal cortex & medulla releases glucocorticoids (cortisol) and catecholamines adrenaline and noradrenaline) Regulation • Under stress, amygdala activates HPA axis • When stress subsides, glucocorticoid 'feedback' regulates ACTH and CRH release by binding to mineralocorticoid (MR) and glucocorticoid (GR) within L-HPA region Cushing's syndrome w/ too much CRF, ACTH, Cortisol (opposite effect of loss of Amyg)
How does NE affect anxiety?
Stressed rats have increased NE release from Locus Coeruleus. NE stimulates CRH activationg HPA axis. Thereby=anxiety
What is a problem associated with psychiatric medications and weight gain?
Strongest correlation for gaining weight is H1 histamine Receptor.
What area of the brain is associated with auditory hallucinations?
Superior Temporal lobe abnormalities. The arcuate fasciculus that connects auditory lobe to frontal cortex may be disconnected. Gray and white matter are affected.
What is the master clock of the brain? Why?
Suprachiasmatic nucleus in anterior hypothalamus. It receives signals from the retina.
How does testosterone influence songbirds?
Testosterone causes song nuclei to be 3x larger in males than females. Females given testosterone will increase volume of high vocal center (HVC) and Robust nucleus (RN). Drops in testosterone correspond to death of HVC
What mesolimbic structure is well connected to OFC? Purpose?
The NAc is well connected to OFC. OFC sends dopamine there and ensures that we get what we are looking for. VTA produces Dopamine and projects to NAc (= mesolimbic dopamine projection). Major pathway for reward. (involved with addiction) NAc also projects to PFC (prefrontal cortex) and amygd. Both pain and pleasure evoke opioid release in amygdala, OFC, NAc, and VP (ventral Pallidum) [Integration of pain & pleasure]
What is the orbitofrontal role in emotion
The OFC is involved in learning to associate a stimulus and an action
What area of the brain is associated with the sleep switch?
The Ventrolateral preoptic nuclei. It is inhibitory to the arousal nuclei during sleep. The VLPO receives inhibition from the hormones that it inhibits, explaining the fast sleep-wake switch.
What area of the brain recognizes a threatening stimulus?
The amygdala - an overactive amygdala can lead to excessive defensive aggression.
How does the amygdala relate to fear?
The amygdala gets info directly from the thalamus and tells you whether or not to trigger a response to fear. Rapid response (fear is more phasic/acute eg predictable shock = central amygdala) VS anxiety which is less acute/tonic unpredictable shock = lateral amygdala, lateral basal nucleus of stria terminalis)
What is the anxiety response?
The brain's alarm system firing during times of perceived danger. Overactive to perceived threats.
What is adaptive thermogenesis?
The brain's way of maintaining consistent weight. Increase in weight = increase in energy expenditure (vice versa)
What area puts the brake on aggression?
The frontal cortex applies brakes to the primitive impulses that arise from subcortical brain. Significant frontal lobe dysfunction is associated with impulsive aggression.
What are the divisions of the Occipital Lobe?
The occipital lobe is divided into a primary visual cortex (BA17), also designated as striate cortex, and a much more extended extrastriate cortex, which corresponds to the occipital visual association areas. White matter tracts = Cingulum, Inferior Longitudinal Fasciculus, Inferior Frontal Occipital Fasciculus
What in the PFC is most closely related to intelligence?
The rate of change of gray matter thickness. Superior intelligence has less gray matter as children, peak later, then show more rapid thinning.
Importance of brain size WRT intelligence?
The relative brain size: body size matters. Larger bodies have larger brains, not always smarter.
What is Visual Alloesthesia?
The world is perceived in an incorrect orientation, for example, inverted, tilted or right-left reversed
What are illicit drugs' long-term effect on NAc?
They alter the dendritic spine formation and cocaine down-regulates DA receptors, its possible effect being to lesion the NAc.
How do cholinergic drugs work?
They enhance Ach in brain by blocking breakdown by mimicking Ach, inhibiting cholinesterase
How do stimulants aid in tx of ADHD?
They increase extracellular DA and NE in the frontal cortex and DA in the striatum by blocking DA and NE reuptake transport.
What are Reduplicative Phenomena disorders?
Thought to relate to disconnection between visual, affective and memory regions due to lesions of the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus In these disorders, familiar people, places and objects are perceived as duplicates that have replaced the real person, place, or object
What role does the cerebellum have in memory?
Timing responses
What type of psychosurgery is performed in the US for OCD? Europe?
US= anterior cingulotomy, based on ACC and basal ganglia. Europe is anterior capsulotomy. May be more effective but also has more side effects.
Why do youth take more risks?
Undeveloped FC. (another reason they are aggressive).
What are the three main causes of drug relapse?
Use of drug, exposure to cues associated with drugs, stress (via HPA axis) HPA = Hypo-pituitary-adrenal
Verbal Paraphasia
Use wrong word "my mother" instead of "my wife"
What areas of the brain are activated during romantic love?
Ventral Tegmental Area Caudate Nucleus (activity correlates to Passionate Love Scale) VTA = addiction CaudN = obsession
What are the central structures of the mesolimbic dopamine system?
Ventral Tegmental Area (VTA) and Nucleus Accumbens (NAc)
What is reconsolidation?
When long term memories return to a labile state and become vulnerable to disruption before being consolidated. Psychotherapy?
How does testosterone differ in "winners and losers?"
Winners experience spike in testosterone. Losers have testosterone levels drop. Socially dominant but not aggressive people generally have higher plasma testosterone.
What is the relation between amygdala activation and sex?
Women LEFT amygdala shows greater connectivity to brain areas to control internal milieu, subgenual ctx, hypoth. Men, RIGHT connected to areas to respond to external stimuli, sensorimotor ctx, striatum, pulvinar
What are sex differences between female and male schizophrenics?
Women have better response because of estrogen. It also appears later for women. They also respond better to antipsychotic medication than men.
For which people does corpus callosum size matter?
Women need a larger corpus callosum to perform mental abilities indicating use of both sides of their brain.
Who is better at verbal skills and fine motor skills?
Women, even better when estrogen is higher. However spatial abilities also decrease when estrogen is high.
Literal Paraphasia
Words are distorted. "Hike...Pike... Pipe"
Genetic relationship of schizo?
YES! (50-80% heritable, 81% concordance rate among monozygotic twins) (but some adopted kids raised in good homes might not develop schizo despite higher risk) [22q11 deletion mimics schizo but not very useful screen]
What are the 5 Frontostriatal Circuits?
[Neurology] • Motor (Primary motor cortex) • Oculomotor (Frontal eye fields) [Psychiatry] • Orbitofrontal cortex (OFC) = phineas gage • Anterior cingulate cortex (ACC) • Dorsolateral prefrontal cortex (DLPFC)
What are the different receptors and classes of peptides associated with endogenous opioids? Exogenous?
μ: Euphoria - dependence (endorphins eg β-endorphins from POMC) δ: Anti-depressant, anxiolytic (enkephalins eg Met- and Leu-) κ: Dysphoria - compliance (Dynorphins eg A, B, α/β-Noendorphin) All these reduce pain despite diff. effects. Most pharmaceuticals act on the Mu opioid receptor (MOR) -> euphoria -> dependence
What are the 4 types of syndromes associated with lesions to the temporal lobe?
• Auditory Perception Syndromes: acoustic radiations from bi MGN's to adjacent areas: Cortical deafness for sounds (right) or words (left) • Language Syndromes: Wernicke's- Transcortical sensory- Anomic- and Conduction- aphasias & receptive aprosodia (detect tone in what ppl saying) • Multimodal Visual Syndromes: Inf. part of temporal lobe connects to occipital: macropsia or micropsia (objects look big or small), Pelopsia or Teleopsia (objects look close or far), Autoscopy, Prosopagnosia, Alexia • Memory and Behavioral Syndromes: Temp lobe includes amygdala and hippocampus (functionally they're limbic system): Semantic dementia, reduced verbal fluency, impaired naming
Frontal Lobes Summary:
• Frontal lobes mediate cognition, comportment, limbic drives. • Frontostriatal circuitry is preserved • Orbitofrontal syndrome = Disinhibited • Anterior cingulate syndrome = Apathetic • Dorsolateral syndrome = Dysexecutive • Formal neuropsychological testing helps detect executive dysfunction.
3 Limbic Lobe Syndrome types?
• Hippocampal-Hypothalamic Syndromes: Amnesias, Alzheimer's disease (early), Korsakoff disease, Topographical disorientation (lose sense of place) • Orbitofrontal - Amygdala Syndromes: Kluver-Bucy syndrome, Visual hypoemotionality, Personality changes • Paralimbic Syndromes: Pain asymbolia (no emotion 2 pain), Altered olfaction (increased or decreased), Apathy, Mood changes (depression, irritability), Semantic dementia, Right olfactory anomia (Other dx assd. w/ LL: Schizo, Autism, Depression/bipolar, Temporal lobe epilepsy, mild cognitive impairment, psychopathy)
What is the Limbic Lobe?
• Includes a core subcortical network (centered around the hippocampus and thalamus) formed by the fornix and mammillothalamic tract, and a group of paralimbic cortical areas connected through the cingulum and uncinate fasciculus. • Other tracts, such as the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus connect the limbic regions to visual and auditory areas. • Cingulum, Uncinate, IFOF, Fornix, Mammillo-thalamic, ILF tracts. (Problems in limbic lobe can lead to memory and emotion problems)
What are the 4 categories of Occipital lobe lesions?
• Primary Visual Syndromes: 1° visual cortex input from LGN connect to extrastriate cortex. Lesions -> scotoma, quadranopia, hemianopia, cerebral blindness & simple hallucinations (phosphenes). • Dorsal Visual Stream Syndromes: 'where' stream: akinetopsia, allesthesia, optic ataxia, motion hallucinations • Ventral Visual Stream Syndromes: 'what' stream: Object agnosia, achromatopsia, Prosopagnosia, Alexia • Complex Visual Syndromes: Disconnection of visual, affective and memory regions: Capgras, Fregoli syndromes. Anton's syndrome, Visual hypoemotionality, visual amnesia.
What are the symptoms of major depressive disorder?
• Sleep disturbances • decreased Interest (anhedonia) • Guilty feelings • decreased Energy • Concentration difficulties • Appetite changes • Psychomotor retardation/ agitation • Suicidality ="SIGECAPS" Criteria for Major Depressive episode: Depressed mood or anhedonia PLUS 4 of these other symptoms for at least 2 weeks
What are the 5 groups of parietal syndromes?
• Somatosensory and Tactile Syndromes: post-central gyrus and connections = pain, temp, touch, vibration impaired sense (hypo-, hyper-, dys- esthesias). Tactile perseveration, polyesthesia, tactile hallucinations, astereognosis, agraphaesthesia, atopesthesia, extinction. • Motor Syndromes: Limb ataxia, optic ataxia, Apraxia, Oculomotor apraxia. • Visuospatial Syndrome: (eg right inferior parietal lobule lesion = motor and somatosensory neglect, or single hemifield visuospatial neglect. Modalities affected together or separately. • Symbolic Thought and Memory Syndromes: Alaculia, Alexia, Agraphia, Conduction aphasia, reduced comprehension, impaired verbal working memory, anomia • Complex Visual Syndromes: Inf. Parietal lobule and post. Parietal gyrus connected to visual areas of temporal and occipital (cross-modal transition zones): defects in ability to integrate memory, vision and proprioception, impaired visual imagery, de-realization, out-of-body experience, Balint syndrome, Gerstmann syndrome.
What are some common causes of frontal lobe injury?
• Traumatic brain injury (against cribiform plate) • Stroke - ACA stroke a/w mesial frontal lobe syndome - ACom aneurysm rupture a/w orbitofrontal syndrome (disinhibitive problems) • Frontotemporal dementia (disinhibition, become dick) • Tumors (olfactory groove meningiomas) • Neurosyphilis
