Bio 420 Exam 4
Regeneration in PNS
-regeneration of axons possible in PNS NOT CNS; schwann cells can secrete neurotropins & allow axon to reattach to target *regeneration tube & as long as cell body is in tact* -exercise enhances peripheral axon regeneration
trisynaptic circuit
1. entorhinal cortex-> dentate gyrus (perforant path) synapses 2. dentate gyrus-> CA3 (mossy fiber) synapses 3. CA3-> CA1 (Schaffer collateral) synapses
short-term sensitization of the aplysia gill-withdrawal reflex
1. habituation 2. huge withdrawal response after not giving stimulation for a long time serotonin is released when tail is stimulated, releases cAMP, activates kinase, leads to voltage gated potassium neuron to stay open longer, increase glutamate release
why do critical periods end?
1. plasticity diminshes when axon growth ceases 2. plasticity diminishes when synaptic transmission matures 3. plasticity diminishes when cortical activation is contrained
3 types of nervous system repair
1. regeneration after injury to axon outside CNS 2. no regeneration (in CNS) 3. limited neurogensis (rare)
what two ways will neurons produce synchronized oscillations?
1. they may all take thier cues from a central pacemaker 2. they may share or distribute the timing function among themselves by mutually exciting or inhibiting one another
status epilepticus
A condition in which seizures recur every few minutes or last more than 30 minutes. requires immediate medical attention
CaMKII
A kinase protein that, once activated by calmodulin, is able to phosphorylate other proteins in the cell, consists of 10 subunits. Subunits have two regions shaped like a pocket knife. The catalytic region performs the phosphorylation reaction. Without the appropriate second messenger, the pocket knife is closed and catalytic region is covered by the regulatory region. With LTP, the pocket knife fails to close completely in the alpha subunits CaMKII is an autophosphorylating protein kinase; each subunit within the CaMKII molecule can be phosphorylated by a neighborinbg subunit, so that the hinge is always open
synaptic consolidation
A process of consolidation that involves structural changes at synapses that happen rapidly, over a period of minutes.
input specificity
A property of some forms of synaptic plasticity such that only the active synapses onto a neuron are modified.
Normally the kinases are tightly regulated and are "on" only in the presence of what?
A second messenger
BCM theory
A theory proposing that synapses are bidirectionally modifiable. Synaptic potentiation results when presynaptic activity correlates with a strong postsynaptic response, and synaptic depression results when presynaptic activity correlates with a weak postsynaptic response. An extension of the Hebb synapse concept, proposed by Bienenstock, Cooper, and Munro at Brown University.
malleability of memories
consolidation: initially labile memory traces transformed into relatively permanent ones by a time-dependent stabilization process reconsolidation: if memory reactivated, can become labile for some time
anatomy of the medial temporal lobe
contains the temporal neocortex, which may be a site of long-term memory storage, and a group of structures interconnected with neocortex that are critical for the formation of declarative memories key structures: hippocampus, entorhinal cortex, perirhinal cortex, and parahippocampal cortex
Henry Head's peripheral nerve regeneration experiment
cut a nerve in his own arm, looked where he regained sensation, 2-6 months later, regained sensation (not all)
you were walking on the sidewalk along university avenue when you almost got hit by a car. in class, you told your friend about it. What type of memory did this require?
declarative
Which type of memory can be accessed for conscious recollection?
declarative memory
you had a great breakfast this morning talked about it with a friend in class. what type of memory is this?
declarative memory
Which of the following examples correctly explains how phenytoin and carbamazepine work to suppress seizures?
decrease the tendency for certain neurons to fire action potentials at a high frequency
What happens to a memory if some neurons in the neural network storing that memory begin dying?
degradation/confusing one memory with another
EEG rhythms
delta <4 hz, deep sleep theta 4-7 hz, occur furing sleeping and waking states alpha 8-13 hz, largest over the occiptal cortex, associated with quiet, waking states Mu: similar in frequency to alpha rhythems but are largest over the motor and somatosensory areas beta 15-30 Hz Gamma 30-90 hz, signal an activated or attentive cortex spindles: brief 8-14 Hz waves associated with sleep ripples: brief bouts of 80-200 Hz oscillations
atonic seizures
drop seizures, akinetic seizures or drop attacks, brief lapse in muscle tone caused by temporary alterations in brain function that usually last less than fifteen seconds begin in childhoos and may persist into adulthood usually last 1-2s involves head and neck muscles, or sometimes whole body rare and can be indicative of lennox -gastaut syndrome
basic mechanisms underlying antiepileptic drug therapies
enhancement of Na+ channel inactivation, reduction of sustained high-frequency repetitive firing actions on synaptic transmission, enhancement of inhibitory neurotransmission, reduction of excitatory neurotransmission actions on neurotransmitter receptors, enhancement of GABAa receptor action, reduction of glutamate receptor action
what is the difference between someone who has a seizure and someone who has epilepsy
epilepsy is diagnosed when a person has recurring seizures
Hebb's Cell Assembly
external events are represented by specific patterns of neurons simultaneously firing in the cortex that are interconnected consolidation: fire together, wire together after learning, activation of part of assembly can activate whole assembly engram: could be widely distributed among the connections that link the cells of the assembly, and it could involve the same neurons that are involved in sensation and perception
simple partial seizures
focal in nature, conscious awareness and memory remain intact, neocortical structures typically involved
complex partial seizures
focal in nature, consciousness is impaired, hippocampal involvement disrupting memory formation
absence seizure
form of seizure consisting of momentary clouding of consciousness and loss of awareness of surroundings
In which of the following instances would you normally expect to have regeneration of axons?
frog with severed optic nerve human motor neuron with cell body in spinal cord and damage to axon outside spinal cord
tonic-clonic seizure
generalized seizure in which the patient loses consciousness and has jerking movements of paired muscle groups
Responses to Faces in Inferotemporal Cortex
neural network model for "engrams, -distributed memory: no single neuron represents specific memory -physical changed of memory leads to modification of synaptic strength
manipulating memories
neurons activated by specific sensry context reactivate same neurons experimentally in different context, results in "false memory" -demonstrates that activation fo certain neuron ensemble may be engram
stimululs selectivity
neurons that respond with a barrage of action potentials to the presentation of some but not all stimuli
mechanisms of long-term LTP in mammals and long-term enhancement of the gill withdrawal reflex in aplysia are similar in that both are dependent upon
new protein synthesis
absence seizures
nonconvulsive; person may become unaware of his or her surroundings and may stare off in space or freeze for 5-30s
low frequency, high amplitude rhythms are associated with what state?
nondreaming sleep states, certain drugges states, or the pathological condition of coma
tonic-clonic (grand mal) seizures
occus when there is a massive discharge of neurons in both cerebral hemispheres; body becomes rigid and jerking is observed tonic-clonic means "stiffness-violent"
what part of the brain is responsible for working memory
prefrontal cortex
NMDA receptor only opens if:
presynaptic activity: glutamate released post-synatpic activity: suffiecient depolarization (to remove Mg2+ block) -Ca2+ influx through NMDA receptor triggers LTP (form of synaptic strengthening)
Parkinson's disease and memory
procedural memory is affected
graceful degradation
representations tend to blend together as neurons are lost, such that one memory gets confused with another
memory ____ strengthens cortical connections
retrieval
a patient with brain trauma cannot remember evetns for two weeks prior to the trauma. which type of amnesia does this symptom indicate?
retrograde amnesia
complex partial with secondary generalized seizure
seizure begins as complex partial type, spreads to involve entire brain and brain stem, becomes "secondarily generalized"
partial seizure
seizure involving only limited areas of the brain with localized symptoms can spread to the whole brain simple: w/o alteration of consciousness complex: w/ alteration of consciousness
information flow through the medial temproal lobe
sensory info-> cortical association areas-> parahippocampal and rhinal cortical areas-> hippocampus (also goes back to corticla association areas) --fornix-> thalamus hypothalamus
the hippocampus and possible declarative memory storage sites
sensory information -> cortical association areas -> parahippocampal and rhinal cortical area-> hippocampus -> fornix-> thalamus, hypothalamus
Alzheimer's disease leads to the degeneration of neurons in the hippocampus and in cortical association areas. the ability to do which of the follwoing tasks would most likely be reatined in a person with mid-stage alzheimer's disease
show improvement on amirror drawing task the day after they first tried it
electrical stimulation of temporal lobe
shows that the temporal lobe may play a special role in memory storage, many people recalled past events while others saw themselves
a person goes to the doctor because quite often they feel not quite right and whenever they get that feeling they start smelling roasted almonds, even though none are present. the doctor later diagnoses these episodes as seizures based on EEG results during the episodes. what class of seizures are they?
simple partial
factors that lower seizure threshold
sleep deprivation, physical illness, emotional stress, excitement/depression, caffeine, alcohol/sedative
functions of the hippocampus
spatial memory- radial arm maze, place cells, grid cells memory consolidation of facts and events possibly- plays a role in working memory, may be essential for building or enhancing memories by connecting new sensory input with existing knowledge, odor discrimination, what happened where
significance of aplysia findings
synaptic plsaticity is the mecchanism of simple learning learned that synaptic strength is involved in learning and memory
the physical change that leads to memory can be the modifcation of ____
synaptic weight
the amplitude of the EEG signal strongly depends on how ____ is the activity of the underlying neurons
synchronous
Striatum and Procedural Memory
t-maze with rats, could imply the formation of a habit for which the striatum codes a sequence of behaviors initiated in the t-maze situation
Magnetoencephalography (MEG)
technique that measures brain activity by detecting tiny magnetic fields generated by the brain much better than EEG at localizing the sources of neural activity in the brain, particularly those deep below the surface, can record rapid fluctuations of neural activity that are much too fast to be detected by fMRI or PET cannot provide the spatially detailed images of fMRI
habituation
tendency of the brain to stop attending to constant, unchanging information
which of the following correctly describes the connection between the atmospheric testing of nuclear weapons and cortical neurogenesis?
the absence of the 14C isotope in cortical neurons of people born before atmospheric testing (i.e., before 1955) indicates that few new neurons are incorporate into the cortex of adult humans
amplitudes in waking states are low because?
the activity level of cortical neurons is relatively high but also relatively unsynchronized which would lead to lower amplitudes
declarative memory
the cognitive information retrieved from explicit memory; knowledge that can be declared facts, events, words and their meanings, history easy to form and easily forgotten
episodic memory
the collection of past personal experiences that occurred at a particular time and place
distributed memory
the concept that memories are encoded by widespread synaptic modifications of many neurons, not by a single synapse or cell
procedural memory
the gradual acquisition of skills as a result of practice, or "knowing how" to do things
memory consolidation
the gradual, physical process of converting new long-term memories to stable, enduring memory codes
anterograde amnesia
the inability to transfer new information from the short-term store into the long-term store
nondeclarative memory includes:
the learning of motor skills, like typing fear conditioning priming
after peripheral nerve damage a muscle fiber is initially reinnervated by regenerating axons from two motor neurons. what would happen if yo then blocked muscle acetylcholine receptors with curare?
the muscle fiber will remain polyinnervated (synapses from both motor neurons will remain)
The BCM theory proposed by Bienenstock, Cooper, and Munro suggested which of the following about the bidirectional nature of LTP and LTD?
Synapses that are active when the postsynaptic cell is only weakly depolarized by other inputs undergo LTD instead of LTP.
Research on spatial learning in rats trained on the water maze task has revealed which of the following?
After ten trials, rats with hippocampal lesions are unable to remember the location of the submerged resting platform.
Karl Lashley studied the effects of various-sized cortical lesions on maze performance in rats. He concluded that the memory deficits were correlated with the size of the lesion but not the location and hypothesized that all cortical areas contribute equally to learning and memory. What is the current interpretation of these experiments?
All cortical areas do not contribute equally to memory, but memories are widely distributed.
area IT
An area of neocortex, on the inferior surface of the temporal lobe, that is part of the ventral visual processing stream; contains neurons with responses to complex objects, including faces, and appears to be involved in visual memory
Schaffer collateral
An axon of a CA3 neuron that innervates neurons in CA1 of the hippocampus. Schaffer collateral synapses exhibit LTP and LTD, forms of synaptic plasticity believed to be important for memory formation.
People who have been in stressful situations may begin to have excessive fear responses to certain sounds or sights. Why would therapists who want to reduce the fear response be interested in memory reconsolidation?
During reconsolidation you might be able to "erase" or minimize the association between certain sights or sounds and the fear reponse.
neurotransmitter receptor types
G-protein coupled (metabotropic) receptors and transmitter-gated ion channels (AMPA and NMDA)
Which of the following have been shown to prevent both long-term LTP or learning/memory?
Inhibiting CamKII before LTP or training Blocking protein synthesis during LTP induction and training Blocking NMDA receptors in hippocampus before LTP or training Inhibiting protein kinase M zeta a day after LTP induction or training
engram
The physical changes in the brain associated with a memory. It is also known as the memory trace.
Pre-synaptic activity at the same time as weak depolarization postsynaptically-> ___ at active synapses
LTD
glutamate receptor trafficking
LTD and LTP disrupt the equilibrium of added and removed AMPA receptors, leading to a net increase or decrease in the capacity of the synaptic membrane for AMPA receptors. capacity is determined by the size of a scaffold of slot proteins
Pre-synaptic activity at the same time as strong depolarization postsynaptically-> ___ at active synapses
LTP
What does "long-term potentiation is synapse specific" mean?
LTP can be induced independently on different synapses of individual neuron
Which is the process by which some experiences, held temporarily by transient modifications of neurons, are selected for permanent storage in long-term memory?
Memory consolidation
Regeneration in CNS
Most CSN fibers never regenerate. CNS oligodendrocytes (instead of Schwann cells) bear growth-inhibiting proteins (nogo) that prevent CNS fiber regeneration. Astrocytes at injury site form scar tissue of chondroitin sulfate that blocks axonal regrowth. -no neurotrophins, no clearance by macrophages, inhibitory molecules, and glia scar
blocking the activation of which fo the following types of receptors would prevent both LTP and memory formation in mammals?
NMDA
What are hippocampal place cells?
Neurons that fire when the animal is in a specific location
LTP and LTD in CA1 of the hippocampus may reflect the bidirectional regulation of which two processes?
Phosphorylation and the number of postsynaptic AMPA receptors
mechanisms of LTP in CA1
Presynaptic activation causes the release of glutamate, which acts on postsynaptic AMPA receptors and NMDA receptors; when glutamate release coincides with depolarization sufficient to displace the Mg2+ blocking the NMDA receptors, then Ca2+ enters the postsynaptic neuron rise in Ca2+ activates two protein kinases: protein kinase C and calcium-calmodulin-dependent protein kinase II (CaMKII) Influx in Ca2+ is linked to the induction of LTP
Which of the following examples correctly explains how benzodiazepines and barbiturates work to suppress seizures?
Prolong the inhibitory actions of GABA
What term best describes the process by which reactivating a memory makes it sensitive just as it had been immediately after the memory was first formed?
Reconsolidation
Protein kinase M Zeta
Sacktor, intracerebral injection of a small peptide called ZIP inhibits PKMzeta, and can erase LTP and memories establised many days before the injection. Suggests that persistent PKMzeta activity maintains changes in synaptic strength by continuing to phosphorylate its substrates. PKMzeta mRNA is translated into proteins when there is strong synaptic activity
anti-nogo (IN-1)
Schwab injected into adult rats after a spinal cord injury and found that about 5% of severed axons regenerated
Which of the following statements about sensitization of the gill withdrawal reflex in Aplysia are true?
Sensitization can last for hours up to days. Sensitization is caused by an increased release of serotonin onto the presynaptic terminal of sensory neurons in the reflex pathway for gill withdrawal. Sensitization results in increased glutamate release from the sensory neuron onto the motor neuron
Which of the following structures is necessary for procedural memory?
Striatum
transient global amnesia
Sudden onset of complete anterograde amnesia and learning abilities, often accompanied by retrograde amnesia for recent events preceding the attack, the person may appear disoriented and ask the same questions repeatedly, working memory like digit span are normal, lasts minutes to days, once the spell subsides the person is left with a permanent memory gap
Schwann cells
Supporting cells of the peripheral nervous system responsible for the formation of myelin.
Which of the following is a requirement for long-term memory?
Synthesis of new protein
What brain structure is known to act as a powerful pacemaker for the cerebral cortex?
Thalamus
perforant path
The axonal pathway from the entorhinal cortex to the dentate gyrus of the hippocampus. Perforant path synapses exhibit LTP and LTD, forms of synaptic plasticity believed to be important for memory formation.
molecular switch hypothesis
The idea that protein kinases can be switched "on" by autophosphorylation to a state in which they no longer require the presence of a specific second messenger to be active. Such persistently active kinases may hold the memory of an episode of strong synaptic activation. Initially proposed by John Lisman at Brandeis University.
multiple trace model of consolidation
The idea that the hippocampus is involved in the retrieval of remote memories, especially episodic memories. This contrasts with the standard model of memory, which proposes that the hippocampus is involved only in the retrieval of recent memories.
effects of hippocampal lesions in rats
The rat uses visual or other cues around the maze to remember where it has already been. Working memory is presumable used to retain information about which arms have been visited. If the hippocampus is destroyed before the rat is put in the maze, they will go down the same arms more than once and never learn to do the maze efficiently variation: only put food down certain arms, rats with and without lesions avoid arms without food, but rats with lesions still go down same arms more than once
The EEG is primarily used to help diagnose certain neurological conditions, especially which of the following?
The seizures of epilepsy
Which of the following abnormalities in EEG voltage patterns is recorded synchronously across the entire brain during absence seizures?
Very large amplitude waves
properties of LTP in CA1
a bundle of presynaptic axons are given a brief electrical stimulus. stimulation is give every minute for 15-30 minutes. next, the same axons are givena tetanus (brief high-frequency stimulation). This evokes an EPSP that is much greater than it was during the initial baseline period. (tetanus caused a modification of the stimulated synapses so they are more effective) LTP in CA1 can last for many weeks, possibly even a lifetime in awake animals high frequency stimulation is not an absolute requirement of LTP. Synapses need to be active at the same time that the postsynaptic CA1 neuron is strongly depolarized. 1. synapses must be stimualted at frequencies high enough to cause temporal summation of the EPSPs 2. enough synapses must be active simultaneously to cause significant spatial summation of EPSPs (cooperativity)
nonassociative learning
a change in behavioral response that occurs over time in response to a single type of stimulus. Two types: habituation and sensitization
systems consolidation
a consolidation process that involves the gradual reorganization of circuits within brain regions and takes place on a long time scale, lasting weeks, months, or even years
lateral intraparietal cortex (area LIP)
a cortical area buried in the intraparietal sulcus that is involved in guiding eye movements; the responses of LIP neurons suggest that they are involved in working memory delayed-saccade task- animal fixates on a point on a computer screen and target is briefly flashed at a peripheral location, then delay period, then fixation point disappears and the animal's eyes make a saccadic movement to the remembered location of the target
Ammon's horn
a layer of neurons in the hippocampus that sends axons into the fornix, contains four divisions like CA3 and CA1
long-term depression (LTD)
a long-term decrease in the excitability of a neuron to a particular synaptic input caused by stimulation of the terminal button while the postsynaptic membrane is hyperpolarized or only slightly depolarized synapses are decreased in their effectiveness, causes loss of AMPA receptors, possibly synapse elimination
semantic memory
a network of associated facts and concepts that make up our general knowledge of the world
working memory
a newer understanding of short-term memory that focuses on conscious, active processing of incoming auditory and visual-spatial information, and of information retrieved from long-term memory temporary storange that lasts for seconds prefrontal cortex mostly
reconsolidation
a process in which previously stored memories, when retrieved, are potentially altered before being stored again
cyclic AMP response element binding protein (CREB)
a protein that binds to specific regions of DNA (cyclic AMP response elements) and functions to regulate gene transcription; a key regulator of protein synthesis-dependent memory consolidation
sensitization
a simple form of learning that occurs when presentation of a stimulus leads to an increased response to a later stimulus
dentate gyrus
a strip of gray matter in the hippocampal formation
Which of the following statements explains why neurons that fire together wire together?
a synapse formed by a presynaptic axon ins strengthened when the presynaptic axon is active at the same time that the postsynaptic neuron is strongly activated by other inputs
what type of neuronal activity is believed to result in the retrieval of a memory, such as the memory of someone's face, based on experimental results
a unique pattern or ratio of activity in specific ensemble of cells, some with increased activity, other decreased
short-term memory
activated memory that holds a few items briefly, such as the seven digits of a phone number while dialing, before the information is stored or forgotten
Induction of LTP in mammals and short-term enhancement of the gill withdrawal reflex (sensitization) in Aplysia are similar in that both are dependent upon
activation of protein kinases.
dissociated amnesia
amnesia not accompanied by any other cognitive deficit
the type of receptor that is critical for the induction of hippocampal LTP, by virtue of its admitting calcium into the postsynaptic cell, is called
an NMDA receptor
Korsakoff's Syndrome
an alcohol-related disorder marked by extreme confusion, memory impairment, and other neurological symptoms associated with lesions in the dorsomedial thalamus and the mammillary bodies, retrograde and anterograde amnesia
standard model of memory consolidation
an explanation of memory formation in which sensory information is processed by the hippocampus and later transferred to neocortex for permanent storage
retrograde amnesia
an inability to retrieve information from one's past
a patient with brain trauma cannot remember events taht have happened since the trauma occurred. Which type of amnesia does this symptom indicate?
anterograde amnesia
Which of the following statements about the clinical case of H.M. are true?
at 27, had 8 cm of medial temporal lobe bilaterally excised, including cortex, amygdala, and anterior two-thirds of the hippocampus It showed that bilateral medial temporal structures are important in the formation of declarative memories (memory consolidation but not for the retrieval of memories) H.M. was unable to remember clinicians who worked with him for many years. H.M.'s nondeclarative memory was intact. Could form procedural memories H.M. had a profound loss of declarative memory functions. Some functions like the floor plan of his new house and could recognize the president. Retrograde amnesia for memories closer to surgery, early childhood memories in tact, might have extended back decades working memory was largely normal
Most generalized seizures are accompanied by rhythmic limb movements which are called __________ muscle activity.
clonic
a person has seizures where they lose muscle control and tone in all their limbes, and lose consciousness. which of the following best describes the type of seizures they have?
complex atonic seizure
causes of epilepsy
genetic: arise from defects in the genes which encode ion channels like voltage-gated K+ or Na+ channels or receptors like GABAa receptor structural: brain tumor, arteriovenous malformation, infection (abscess, encephalitis), excess spinal fluid (hydrocephalus), scar tissue metabolic: hypoglycemia, hypocalcemia, drug use or abuse, acute encephalopathy other abnormalities: electrolyte abnormalities, high fever, stroke, neurodegenerative disorder unknown
axon regeneration can occur in the pns, but not within the brain and spinal cord. describe two differences between the PNS and CNS which allow for regerative axons growth in the PNS, but not the CNS, and briefly explain how they influence the growth
glia in CNS (oligodendrocyts mostly) express inhibitory factors that inhibit axon growth, while schwann cells in peripheral nerves secrete neurotrophic factors that promote growth proliferation of glia in CNS form a physical barrier that prevents growth past that point (glia scarring), but in PNS debris is cleared by macrophages and remaining extracellular matrix actually provides a conduit for axonal growth axon damage in CNS results in death of neurons due to loss of trphic factors in target and substances released by microglia, but damaged to PNS nerves results in schwann releseaing neurotrophic factors which keep neurons aline
The NMDA receptor is only activated (channel opened) when
glutamate binds to the receptor while the membrane is depolarized
can axons grow in adult CNS?
goldfish and songbirds: testosterone->VEGF-> BDNF-> neurogenesis -BrdU, birth dating to confirm adult neurogenesis, neuronal markers and morphology, connections
Huntington's disease and memory
have difficulty learning tasks in which a motor response is associated with a stimulus
Which of the following describes the EEG recording from an awake, active and thinking individual?
high frequencies and low amplitude waves
long-term potentiation (LTP)
high-frequency stimulation of presynaptic neuron causes long-term increase in EPSP of post-synaptic cell -leads to insertion of additional glutamate receptors -Ca2+ influx through NMDA receptor initiates LTP
LTP is caused by
high-frequency stimulation of presynaptic neuron causes long-term increase in EPSP of post-synaptic cell can be temporal or spatial summation which causes sufficient depolarization to enable NMDA receptor actication (channel opening) LTP is artificially induced, but similar processes likely underlie memory formation
adult neurogenesis is thought to influence memory by increasing neurons in which grain region
hippocampus
initial memory storage is in the ____
hippocampus
which of the following is the definition of working memory?
holding and mentally manipulating information in some way
Courtney et al study to image working memory
identity task-memorize faces and then shown many faces and asked if they were one of they faces they were asked to memorize, location task- memorize locations of faces, asked if faces were in same location, used PET and found six areas in the frontal lobe showed significant sustained activity during the delay period, three areas were stronger for identity, one more for spatial, and two were similar for both
medial temporal lobes (including hippocampus) and declarative memory
important for memory formation especially declarative short-term and long-term memories working memory= fine not important for long-term storage
at what locations are newly born neurons found in adult primates?
in hippocampus
protein synthesis and memory consolidation
in order for short-term memories to be consolidated to long-term memories, new protein synthesis must occur during the consolidation
when a person has a seizure, the amplitude of EEG voltage/waveforms ____ and the frequency usually ____, in comparison to EEF waveforms when the person is awake and alert, but not having a seizure
increases, decreases
Does LTP mechanisms underlie memory?
indirect evidence: -inhibitors of LTP also inhibit memory, inhibition of NMDA receptors, certain kinases and protein synthesis block memory formation -LTP_like enhancement of EPSPs after avoidance learning -increased NMDA receptors= increased learning
Which of the following is the principal reason that neurons do not effectively regenerate their axons in the CNS?
inhibitory factors prevent axonal regeneration in the CNS
declarative memory formation
involves a system of interconnected brain structures that take in sensory information, make associations between related info, consolidate learned info, and store engrams for later recall. Includes hippocampus, cortical areas around hippocampus, diencephalon, neocortex, and more.
generalized seizure
involves the entire cerebral cortex of both hemispheres most common type of epilepsy main types: tonic-clonic, myoclonic, absence, atonic uncontrollable discharge of cortical neurons on both sides of the brain start in one area and spread across the brain may produce muscle twitches, confulsions all involve loss of consciousness and typically without warning people with epilepsy type do not remember having a seizure
myoclonic seizures
involves the motor cortex and causes twitching or jerking of certain parts of the body
other treatments for epilepsy
ketogenic diet: high fat-low carbohydrate diet initiated after starvation vagus nerve stimulation (VNS), chronic stimulation of left vagus nerve biofeedback combination surgery: resective surgery (temporal lobectomy, focal cortical excision, hemispherectomy), disconnective surgery (functional hemispherectomy, corpus callosotomy, multiple subpial transection)
lasting synaptic effects of strong NMDA receptor activation
leads to bigger EPSPs
spatial memory and place cells
learning morris water maze requires hippocampus place cells fire when animal is in a specific place
associative learning
learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning). Examples: classical conditioning, instrumental conditioning
no presynaptic activity during depolarization leads to ___
little to no change (no LTP or LTD)
After firing several short bursts of action potentials in an axon, researchers observed a larger EPSP in the postsynaptic cell than before the stimulation, and this larger EPSP lasted for several hours. The phenomena they observed is called ___________________.
long-term potentiation
after firign several short bursts of action potentials in an axon, researchers observed a larger EPSP in the postsynaptic cell than before the stimulation, and this larger EPSP lasted for several hours. the phenomena they observed is called _____.
long-term potentiation
after firing several short bursts of action potentials in an axon, researchers observed a larger EPSP in the postsynaptic cell than before the stimulation, and this larger EPSP lasted for several hours. The phenomena they observed is called ______
long-term potentiation (LTP)
which of the following statements correctly reflects the idea of memory consolidation?
memory consolidation converts short-term memories or sensory information into long-term memory
nondeclarative memory
memory whose formation does not depend on the hippocampal formation; a collective term for perceptual, stimulus-response, and motor memory motor skills, associations, priming cues, puzzle-solving skills
mechanisms of LTP
most typical: Ca2+ influx through NMDA receptor initiates LTP, activates kinases, which leads to increased conductance of AMPA receptors, or insertion of additional glutamate receptors (both things increase response to presynaptic neurotransmitter release) Long-term maintenance dependent on changes in protein snthesis, such as PKMz
Alzheimer's pathology
the severity of the dementia in Alzheimer's disease is well correlated with the number and distribution of what are now commonly known as neurofibrillary tangles, the tombstones of dead and dying neurons the major components of the tangles are paired helical filaments (long fibrous proteins braided together like strands of a rope) These filaments consist of the microtubule-associated protein tau. Normally, tau is a bridge between the microtubules and axons, in Alzheimer's, tau detaches from the microtubules and accumulates in the soma. This causes axons to wither. What causes changes in tau? the abnormal secretion of amyloid
cognitive map theory
the theory that the main function of the hippocampus is to store memories of spatial location
instrumental conditioning
type of learning in which a behavioral response can be conditioned through reinforcement - either punishment or rewards associated with undesirable or desirable behavior
Which of the following brain areas are most important for language-related memory, such as the meaning of words?
upper left temporal lobe
LTP, LTD, and memory
use inhibitory avoidance conditioning (foot shock in a dark room), observed the hippocampus at CA1 synapses and observed LTP, no foot shock=LTD Susumu Tonegawa, knocked out the gene for one subunit of CaMKII, and found parallel deficits in hippocampal LTP and memor. restricted the genetic deletion of NMDA receptors to the CA1 region in mice, striking deficit in LTP, LTP, and water maze performance, revealed an essential role for CA1 NMDA receptors in this type of learning
What part of the nervous system generates the fluctuations and oscillations that are measured by an EEG?
voltages generated by the currents that flow during synaptic excitation of the Dendrites of many pyramidal neurons in the cerebral cortex
case of N.A.
was stabbed with a fencing foil. It went through his right nostril and left a lesion in his left dorsomedial thalamus. After recovery, N.A's cognitive ability was normal, but his memory was impaired. Severe retrograde amnesia for about 2 years preceding the accident, could remember some faces and events from the years following the accident, these memories were sketchy. Similar to H.M.'s case. preservation of short-term memory, the recollection of old memories, and general intelligence, difficulty forming new declarative memories, retrograde amnesia
synaptic tagging and capture
weak tetanic stimulation activates briefly only a small number of synapses and decays back to baseline over the course of an hour or so repeated episodes of strong stimulation recruits a larger nubmer of synapses and induces long-lasting LTP because it stimulates new protein synthesis
Which of the following statements explains why neurons that fire out of sync lose their link?
when the presynaptic axon is active and, at the same time, the postsynaptic neuron is weakly activated by other inputes, then the synapse formed by the presynaptic axon is weakened
habit learning in humans and nonhuman primates
when the striatum is damaged, the animal is unable to form the habit of always retrieving food associated with one visual stimulus rather than another.
would you expect a perosn with Parkinson's disease to have memory problems, and if so, what type?
yes, non-declarative memory
