Exam 5 Flashcards
1
Q
Memory can by classified in two dimensions. What are they?
A
1) the time course of storage
2) the nature of the information stored.
2
Q
True/false: short term and long term memory involve different neural systems
A
True
3
Q
the ability to store information depends on short-term memory, called _______
A
Working Memory
4
Q
In humans working memory consists of at least two subsystems. What are they?
A
1) The verbal information subsystem
2) The visuospatial information subsystem
5
Q
What is working Memory?
A
It maintains current, albeit transient, representations of goal-relevant knowledge.
6
Q
The functioning of the two subsystems of working memory (verbal and Visio spatial) are coordinated by a third system called________
A
The executive control processes
7
Q
What is the function of executive control processes?
A
1- Executive control processes are thought to allocate attentional resources to the verbal and visuospatial subsystems
- and to monitor, manipulate, and update stored representations.
8
Q
When is the verbal subsystem of working memory used?
A
We use the verbal subsystem when we attempt to keep speech-based (phonological) information in conscious awareness.
E.g. when we mentally rehearse a phone number just obtained from an operator.
9
Q
The verbal subsystem of working memory consists of two interactive components. What are they?
A
1) a store that represents phonological knowledge
2) a rehearsal mechanism that keeps these representations active while we need them.
10
Q
What is the function of the Visio spatial subsystem in working memory?
A
The visuospatial subsystem of working memory retains mental images of visual objects and of the location of objects in space.
11
Q
What is memory?
A
The process by which knowledge is encoded, stored, consolidated and retrieved.
12
Q
What is learning?
A
A Change in behavior that results from acquiring memories (knowledge about the world)
13
Q
True/false: different aspects of learning and memory are mediated by specific brain properties and brain systems.
A
True
14
Q
What is Memory storage?
A
The neuronal processes allowing for a memory to be retained over time.
15
Q
What is Encoding?
A
The process by which new information is registered/attended and linked to existing information
16
Q
What is Memory retrieval?
A
The process by which stored information is recalled.
It is much like perception: it is a constructive process subject to distortion much like perception is subject to illusions.
17
Q
What is Memory consolidation?
A
The process that makes the temporarily stored and still labile information more stable.
It involves the structural modification of synapses through gene expression
18
Q
What are the 4 main processes involved in Memory formation?
A
- Encoding
- Storage
- consolidation
- Retrieval
19
Q
In the time course dimension, memory is classified as _____ or ______
A
Short term
Long term
20
Q
Based on the nature of information dimension, memory is either classified as _____ or ______
A
Explicit
Implicit
21
Q
Which area of the brain maintains a working memory when performing a task?
A
The prefrontal cortex
22
Q
Neurons in the prefrontal cortex encode _____ and ______ but most prefrontal neurons encode _______
A
Spatial location (where)
Identity (what)
Both representations (what and where)
23
Q
Long term memory results from the ________ of information encoded first as a short-term memory.
A
Storage and consolidation
24
Q
Long term memory is either ______ or _______
A
Explicit
Implicit
25
What is implicit memory?
Non-declarative or procedural memory
It is an unconscious form of memory evident during the performance of a task. E.g. reading the words of a song for example
26
What is explicit memory?
Declarative Memory
It is a conscious form of memory that requires the retrieval of previous experiences and factual knowledge about people, places, and things.
E.g recalling the first time hearing a song
27
Which type of memory is more flexible: explicit or implicit?
Explicit
28
How is explicit memory more flexible than implicit memory?
In explicit memory multiple pieces of information can be associated under different circumstances.
In implicit memory- memories are more tightly connected to the original conditions under which learning occurred.
29
Is implicit memory Independent or dependent on the hippocampus?
Independent
30
Is explicit memory Independent or dependent on the hippocampus
Dependent
31
Priming is a type of ______(explicit/implicit) type of memory.
Implicit
32
What is priming?
A form of memory generated by the repeated exposure to a given stimulus. It refers to unconscious memory formed when the brain is passively exposed to a stimulus.
33
There are two types of priming. What are they?
1. Conceptual priming
2. Perceptual priming
34
What is conceptual priming?
It is based on the meaning of a stimulus and refers to task relevant semantic knowledge that has been used before.
E.g. associating the word democracy with election.
35
What is perceptual priming?
It is based on the form of a stimulus and is therefore modality specific.
E.g. associating the letters DEM with the word democracy.
36
Which part of the brain does conceptual priming require?
The prefrontal cortex
37
Which part of the brain does perceptual priming require?
Sensory cortices
38
Procedural memory is an ____(explicit/implicit) type of memory
Implicit
39
What is procedural memory?
It refers to the learning of motor, perceptual or cognitive skills.
40
True/false: some implicit memories are at first explicit.
True: e.g. learning to play an instrument. At first you need to pay attention, eventually with enough practice you can play it without being conscious of playing it.
41
Different types of procedural memories require different brain centers. These brain centers are: _______(3 of-them)
1. Basal ganglia
2. Cerebellum
3. Different cortices
42
Non-associative memory is an (explicit/implicit) type of memory.
Implicit
43
What is non associative memory?
It results from the single or repeated exposure of a subject to a stimulus.
The subject learns about the property of a single stimulus.
44
There are two kinds of non-associative memories. What are they?
1. Habituation
2. Sensitization
45
What is habituation?
A decrease in response to a stimulus that occurs when a benign stimulus is presented repeatedly.
46
What is sensitization?
An increase in response to a stimulus that occurs after the presentation of a noxious stimulus.
47
Associative Memory is an ____(explicit/implicit) type of memory.
Implicit
48
What is associative memory?
Classical conditioning. It results from the pairing of two stimuli: an unconditioned stimulus and a conditioned stimulus.
49
What is an unconditioned stimulus?
On its own, it normally induces a strong and consistent response.
E.g. a loud scream will startle you
50
What is a conditioned stimulus?
On its own, it normally induces a weak response
E.g. a picture of a cute cat will likely elicit no particular response other than a fuzzy loving feeling.
51
True/false: in associative memory, the value of the unconditioned stimulus is transferred onto the conditioned stimulus.
True
52
True/false: in associative memory, repeated exposures to the combination of the unconditioned and conditioned stimuli lead to the conditioned response: the association between the two stimuli.
True
53
Explicit Memory is a form of______ memory
Long term memory
54
What is explicit memory?
It refers to knowledge acquired with a conscious effort
55
Explicit memory can be divided into two types. What are they?
1. Episodic Memory
2. Semantic memory
56
What is episodic memory?
Memory of personal experience or autobiographical memory.
E.g. the first time you heard a specific music artist
57
What is semantic memory?
The memory of concepts
E.g. the meaning of the word democracy
58
True/false: storage of long term explicit memories takes place in one brain region.
False. Storage of any item of knowledge is distributed across different regions.
59
The formation of episodic Memories involves the interaction between several brain centers including the ________ and the _______, a large brain region that includes the hippocampus.
Prefrontal cortex
Medial temporal lobe.
60
Lesions in the ________ affect all four processes of memory encoding, storage, consolidation and retrieval
Medial temporal lobe.
61
Patient’s that have damage to the medial temporal lobes can still recall ______memories. This suggests that these kind of consolidated memories do not require the medial temporal lobe.
Long term episodic memories.
62
Semantic memory is much more flexible than episodic memory. Why?
It contains various information about an object or a concept that can be recalled independently of each other.
63
True/false: in semantic memory, each concept is most likely stored in a distributed manner across the entire neocortex.
True.
64
Long term _______ Memory is not associated with the context in which the information was acquired.
Semantic memory.
This is in contrast to episodic memory which is associated with context.
65
True /false: Memory is not perfect and sometimes distorts the past.
True:
66
Memory failures can be divided into 7 categories. What are they?
1. Transience
2. Absent mindedness
3. Blocking
4. Misattribution
5. Suggestibility
6. Biases
7. Persistence
67
What is transience?
It refers to the decreasing accessibility of memory over time.
68
What is absent mindedness?
A Memory failure that results from the lack of attention to immediate experience.
It can lead to failures in encoding
Working memory has a limit on the amount of information it can handle, so abscent mindedness during studying can lead to failures in encoding information properly.
69
What is blocking?
A memory failure that leads to the inability to retrieve in full or in part, the information stored in a memory.
This can result when information is not encoded properly
70
What is misattribution?
A Memory failure that results from the formation of a memory that contains incorrect information. E.g a different place or person.
It can be due to simple defects in perception. E.g. misseeing a color
71
True/false: the hippocampus has different activity when a person is remembering true or false events (misattributed events)
False:
The levels of activity are similar
72
What is suggestibility?
A Memory failure that results from the tendency to incorporate external information into memories, usually as a result of leading questions or suggestions.
73
What are biases?
A type of memory failure resulting from distortions and unconscious influences on memory that tend to reflect the general knowledge and beliefs of a person, but also reflect the biases already present in the immediate environment of a person.
74
What is persistence?
A type of memory failure resulting from obsessive memories. A constant remembering of emotional events that we might want to forget.
Obsessive memories elicit activity in the amygdala (the brain centers involved in emotion during the retrieval of emotionally charged memories).
75
True/false: episodic Memory in particular is a constructive process and is the product of sensory perception (not a simple recording of the external world)
True
76
Priming takes place in the ________
Neocortex
77
Procedural Memory occurs in the______.
Striatum
78
Associative memories take place in the _______ and _______
Amygdala
Cerebellum
79
Non-associative memories involve the ______
Reflex pathways
80
Aplysia californica is a ______ that can learn with a brain of about ______neurons
Snail (marine mollusk)
20,000
81
Apylsia californica is an ideal organism for studying _______ type of memories because ____
Implicit
It has large easily accessible neurons allowing for easy electrophysiological and molecular studies.
82
What is habituation?
An implicit, non-associative type of memory that allows for the ability to block stimuli. I.e. a decrease in the response to a stimulus observed when the stimulus is repeated.
It is one of the simplest forms of memory.
83
Sherrington suggested that habituation is caused by diminished ________
Synaptic effectiveness
84
What happens in diminished synaptic effectiveness?
The intensity of the reflex diminishes over time.
At first, stimulation produces a strong EPSP in the motor neuron and inter neuron leading to further activation of the motor neuron. The sum of the two EPSPs produces a vigorous response reflex.
When the stimulus is repeated several times, the EPSP produced in the motor neuron and inter neuron diminishes in size.
85
The reduction in synaptic transmission seen during habituation is called _______
Synaptic depression
It can last for many minutes
86
True/false: in habituation, the sensitivity of the glutamate receptor changes.
False:
It does not change.
87
In habituation, synaptic depression (homosynaptic depression) occurs because______
The reduction occurs in a neuronal circuit and does not require a modulatory neuron.
88
In habituation, the amount of glutamate released by the sensory neuron _______(increases/decreases)
Decreases
Thus the number of synaptic vesicles released is fewer following an action potential.
89
True/false: habituation can be a short term memory or a long term memory.
True
90
Long-term habituation can be stored up to ______ weeks depending on how many times the stimulus was repeated.
3
91
Can all synapses habituate?
No
The strength of some synapses rarely changes, even with repeated activation.
92
What causes long term habituation?
A decrease in the number of synaptic contacts made between the sensory neuron and the motor neuron.
93
Habituation results from a decrease in ______
Synaptic transmission efficiency
94
True/false: A homosynaptic depression can last for minutes (short term) or last for weeks (long term)
True
95
True/false homosynaptic depression can occurs at different sites, thus it is a distributed form of memory and stored across the brain.
True
96
What is sensitization?
A implicit non-associative form of memory that can be short term or long term.
It results from an increase in response to a stimulus (usually in response to a harmful stimulus)
97
Sensitization results from ______
Enhanced synaptic transmission at several sites in the circuit
I.e. an increase in synaptic transmission efficiency.
98
In short term sensitization, the facilitating neuron is activated and releases ______ (neurotransmitter) at different synapses
Serotonin
99
In sensitization, the serotonin receptor is a ______protein coupled receptor expressed by _____ and ______neurons.
G
Sensory
Motor
100
In short term sensitization, the serotonin receptor activates an ______ via Gs protein and a ______ via a Gq/11 protein
This modifies synaptic transmission
Adenylyl cyclase
Phospholipase kinase c
101
Activation of adenylyl cyclase is one way to modify synaptic transmission in short term sensitization.
How does it do this?
1. The adenylyl cyclase increases the concentration of cAMP
2. cAMP activates a kinase called PKA.
3. PKA then phosphorylates K+ channels which decreases the K+ current during action potentials
4. As a result, Ca2+ influx increases through t the voltage gated Ca2+ channels, which enables the synaptic release machinery acting on the reserve transmitter pool, mobilizing more vesicles for release
102
Activation of the phospholipase kinase c is another way to modify synaptic transmission in short term sensitization.
How does it do this?
1. It phosphorylates targets in the synaptic release machinery which then acts on the reserve transmitter pool, mobilizing even more vesicles for synaptic release
103
Long term sensitization results from prolonged neuronal activity and involves the ______pathway
CREB
104
True/false: long term sensitization can be detected after spaced Training.
True
105
In long term sensitization, a prolonged rise in __levels prolongs the activation of _____
CAMP
PKA
106
In long term sensitization, the prolonged activation of PKA leads to the release of its catalytic subunit, which can the translate to the nucleus and activate a _____ for CREB-1
Prolonged PKA activation also causes the activation of _____, which release the inhibitory action of the _______ for CREB-2
Transcription factor
MAPK
Transcription factor
107
In long term sensitization, CREB-2 is a _____. And CREB-1 is a ______.
The presence of both of these in the first step of long term sensitization suggests what?
Transcriptional repressor
Transcriptional activator
It suggests that the threshold or long term memory storage can be regulated (probably by mood, attention and social context)
108
In long term sensitization, degradation of the _______enables neurons to sustain a memory even if cAMP is back to its basal level.
PKA regulatory subunit
109
In long term sensitization, how is the transcriptional activity of CREB facilitated?
Phosphorylated CREB-1 associates with coactivator CBP, which acetylates the histones surrounding the CREB regulatory element (CRE) and opens the nucleosomes.
110
In long term sensitization, ubiquitin carboxyterminal hydrolase is a transcriptional target that does what?
It enhances PKA activity by degrading regulatory subunits
111
In long term sensitization, the transcriptional factor C/EBP is a transcriptional target that does what?
Promotes the growth of new synapses
112
During long term sensitization the number of pre synaptic terminals ______(increases/decreases) between the sensory neuron and the motor neuron. This ______ the connection between these neurons.
Increases
Strengthens
113
Sensitization is often modulated by______ that can act on many different synapses
Modulatory neurons
114
In sensitization heterosynaptic process can last for minutes and form a _______memory or weeks, forming a ______ Memory.
Short term
Long term
115
True/false: heterosynaptic depression has many different effects on neurons and therefore takes place through the same molecular pathways.
False. It takes place through different molecular pathways
116
True/false: associative learning is a complex form of implicit learning.
True
117
In habituation and sensitization, an animal learns about the properties of _____ (provide a #) stimulus
One
118
In short term associative memory, an animal learns to associate _____(provide a #) stimuli.
Two
119
In associative memory, during conditioning, the value of the _____stimulus is transferred to the ____stimulus.
Unconditioned stimulus
Conditioned stimulus
120
For associative learning to be the most effective, the ______stimulus must precede and thus predict the ________stimulus.
Conditioned stimulus
Unconditioned
121
What is a conditioned response and what is an example?
A formerly neutral stimulus that, after associated with an unconditioned stimulus, comes to produce a conditioned response.
E.g. a dog bringing back the ball back to the owner to get a treat.
122
What is an unconditioned stimulus and what is an example?
An unconditioned stimulus triggers an automatic response without any prior learning.
E.g. the dog salivating over a treat.
Or when a loud noise occurs people jump
123
True/false: In associative memory, training to a conditioned stimulus elicits a stronger EPSP.
True
124
True/false: in training, when the unconditioned response proceeds the conditioned stimulus, a weaker EPSP is seen
True
125
If memory is a common trait in Animal behaviors, it must have a _______
Genetic basis
126
Associative memory results from an increase in _____
Synaptic transmission efficiency
127
Associative learning often relies on a coincidence detector. What is a coincidence detector?
A molecule that integrates the temporal pattern of stimulation.
128
For an associative memory to form, it is important that the ____- stimulus precedes or predicts the _______stumulus.
Conditioned
Unconditioned
129
The amygdala is involved in emotions such as ______
Innate and learned fear
130
The amygdala receives input from the _______
Sensory systems
131
The amygdala sends output to many brain centers including the ________, which generates the _______component of emotions such as changes in heart rate and respiration
Brain stem
Visceral
132
Information from an innately fearful stimulus (eg scream or electric shock) is received by the amygdala directly from the ______.
The amygdala receives information about learned fearful stimuli (eg image of a clown) indirectly from the _______
Both the direct and indirect pathways converge on the ________of the amygdala to process and compare sensory information
Thalamus
Cortex
Lateral nucleus
133
The lateral nucleus of the amygdala connects to the ______which mediates fear responses
Central nucleus
134
True/false: many aspects of personality is guided by implicit memory
True
135
The formation of ______\ memories requires transfer of information between brain centers.
Long term memories
136
________memories are maintained in the prefrontal cortex but eventually transferred to the temporal lobe (a center that contains the hippocampus) when they are consolidated
Short term memories
137
Long therm memories are eventually transferred and stored in the ______
Cortex
138
The _________ is the region of the brain that maintains working memory during the task in the monkey Experiment.
Prefrontal cortex
139
What is persistent activity?
Persistent activity is neural firing that continues after the triggering stimulus goes away.
(Working memory)
140
Persistent activity results from_________
The intrinsic cellular properties of prefrontal cortex neurons or their connections.
141
Cellular mechanisms of working memory:
1. A brief depolarizing stimulus on to a _________ neuron in the prefrontal cortex causes a brief burst of action potentials. Followed by an After depolarization.
2. Longer depolarizing stimuli cause larger bursts of action potentials and a longer after-depolarizations.
3. If the depolarizing stimulus is large enough, the after depolarization is capable of___________
Pyramidal cells
Generating a sustained burst of action potentials that can lasts for seconds to minutes.
142
Working memory cellular mechanisms:
In the prefrontal cortex neuron, the influx of Ca2+ through voltage gated channels (VGCC) generated during an action potential opens a _______or CAN.
The influx of Ca2+ through CAN maintains the depolarized neuron and further activates ______ generating persistent bursts of activity.
Ca2+ gated non selective channel
VGCC
143
Persistent activity can result from _____ and _______ mechanisms
Cellular
Network
144
Persistent activity can also result from network properties such as a ___
_recurrent network of interconnected neurons
145
Working memory network mechanisms:
In persistent activity a recurrent network of interconnected neurons consists of two groups of neurons each receiving excitatory inputs. These two groups of neurons _____ each other
The Nero s in both groups fire spontaneously at the basal level that is maintained by ______
Such recurrent interactions can occur between two distant groups of neurons or more locally between groups of neurons within a center.
Inhibit
Reciprocal inhibitory connections.
146
The brain center that is required for planning complex cognitive behaviors (e.g. decisions) is the ______
Prefrontal cortex
147
The prefrontal cortex orchestrates _____ and ______ in accordance with internal goals.
Thoughts and actions
148
The prefrontal cortex carries out an ______ function whereby it can differentiate between conflicting thoughts by determining what is good from bad, better from best, same from different.
It can also predict the most possible outcome of an action
Executive function
149
Working memory is a form of ______ memory that is retained when an animal is performing a task.
Short term
150
Working memory requires ____across a network of neurons
Persistent activity
151
Through persistent activity a ______ can be maintained from seconds to minutes
Representation (eg of a place or object)
152
True/false: deficits in The prefrontal cortex leads to severe cognitive problems.
True (working memory depends on the prefrontal cortex)
153
Is working memory restricted to the prefrontal cortex?
No!
It is most likely distributed across many other brain regions.
154
What is long-term potentiation (LTP)?
A molecular Memory mechanism that has been studied predominantly in the hippocampal formation
It refers to the changes that occur at a synapse during memory formation
155
Long-term potentiation
The hippocampal formation includes 3 structures what are they?
1. The hippocampus
2. The dentate gurus
3. Subiculum
156
Long-term potentiation
The hippocampus is the site where ______memories are formed and stored.
Explicit memories (Memories about experienced events)
157
Long-term potentiation
The hippocampus is also the site where ______ knowledge is stored among a system of place cells.
Spatial knowledge
158
Long-term potentiation
The hippocampus receives input from the _____.
Entorhinal cortex
159
Long-term potentiation
What is The entorhinal cortex?
A brain center that processes multi sensory information as well as spatial information
160
Long-term potentiation
Connections from the entorhinal cortex to the hippocampus ate separated into two pathways. That are they?
1. The direct pathway
2. The trisynaptic pathway (or perforant pathway)
161
Long-term potentiation
the direct pathway between the hippocampus and the entorhinal cortex is formed from _____
The layer III neurons of the entorhinal cortex
162
Long-term potentiation
The trisynaptic pathway from the entorhinal cortex to the hippocampus is formed from_____
Layer II neurons of the entorhinal cortex
163
Long-term potentiation
The hippocampus send output through the _______ which projects back to the entorhinal cortex and subiculum.
CA1 pyramidal neurons
164
Long-term potentiation : hippocampal circuit
The direct pathway comprises the entorhinal II neurons connecting directly to the pyramidal neurons of the _____ region
CA1
165
Long-term potentiation: hippocampal circuit.
The trisynaptic pathway starts with the layer II entorhinal neurons connecting to the ______ cells of the ______\
Granule cells
Dentate gurus
166
Long-term potentiation: hippocampal circuit
In the trisynaptic pathway, the granule cells connect to the pyramidal cells in the _____region (a connection also known as the mossy fiber pathway)
CA3
167
Long-term potentiation: hippocampal circuit
The CA3 pyramidal neurons in the trisynaptic pathway connect to the ______ neurons of the ______ region (a Connection also known as the Schaffer collateral pathway)
Pyramidal neurons
CA1
168
Long-term potentiation: hippocampal circuit
Both the direct and trisynaptic pathways are necessary for the formation of _____ memory
Long term
169
Long-term potentiation: hippocampal circuit
What do the CA1 pyramidal neurons do?
Compare information received from the direct and trisynaptic pathways during memory formation.
170
True/false: Long-term potentiation can be observed at all synapses in the hippocampus
True
171
Long term potentiation:
In the hippocampus LTP is mediated by ____ and _____ receptors
NMDA
AMPA
172
Long term potentiation:
The NMDA receptor is permeable to _____
Whereas, the AMPA receptor is permeable to _____
Cations
Na+ and K+
173
Long term potentiation
The NMDA receptor is both ____and ___ gated
Glutamate
Voltage
174
In Long term potentiation. At resting membrane potential, _____ binds to and blocks the pore of the NMDA channel.
When the membrane depolarizes and ____ is present, Mg2+ is expelled from the pore and the channel opens
Mg2+
Glutamate
175
True/false: most excitatory synapses in the brain contain both AMPA and NMDA receptors.
True
176
Long term potentiation
Because the activation of the NMDA receptor requires both a ligand and depolarization, it is considered to be a ______.
Coincidence detector
177
Long term potentiation
The NMDA can transform _____ signals into _____ones
Because NmDA is ___it generates at ca2+ influx which activates calmodulin and the gene network necessary to increase synaptic efficiency
(this is the molecular bases for Long term potentiation)
Electrical
Chemical
Nonselective
178
Long term potentiation events
How is LTP induced? (3 major events)
1. During normal, low frequency synaptic transmission, the glutamate released by pre synaptic neurons binds to the AMPA and NMDA receptors but the NMDA receptors are blocked by Mg2+
2. During high frequency synaptic transmission, more glutamate is released by the pre synaptic neurons and the AMPA receptors are strongly activated causing release of the Mg2+ inhibition onto the NMDA receptors.
3. Ca2+ can then flow through the (nonselective) NMDA receptors into the post synaptic neurons activating effectors including calmodulin and its targets
179
Long term potentiation
How is LTP expressed? (2 major events)
1. Phosphorylation of theAMPA receptors by different kinases, including PKC, increases the current generated by glutamate
2. Retrograde messengers released by the post synaptic cell modify the pre synaptic cell and enhance the release of glutamate
180
Long term potentiation
Stimulation of granule cells in the mossy fiber pathway (CA3 region) induces _____ of the synapse between the granule cells and the CA3 pyramidal neurons
Long term potentiation
181
Long term potentiation- mossy fiber
Ca2+ influx in the CA3 pyramidal neurons activated ______, which serves to activate an adenylyl cyclase which generates cAMP.
cAMP then activates ____. Increased PKA activity leads to an increase in the release of glutamate by the granule cells and eventually Long term potentiation
Calmodulin
PKA
182
Long term potentiation- mossy fiber
Because activity in the post synaptic cell (CA3 pyramidal Neuron) is not required for this form of Long term potentiation, it is considered to be a form of _______ Memory
Non-associative
183
Long term potentiation : Schaffer collateral pathway (from CA3 to CA 1 in tri synaptic)
Stimulation of CA3 pyramidal neurons in the Shaffer collateral pathway induces Long term potentiation of the synapse between the ____ neurons and the _____ neurons
CA3 Pyramidal
CA1 pyramidal
184
Long term potentiation: Schaffer collateral
Glutamate released onto the____ neurons (combined with their depolarization) induces the opening of the NMDA receptors.
Because NmDA is non selective, it cases an increase in ____ which in turn activates many downstream effectors of long-term potentiation such as CaMK, PKC and tyrosine kinase
CA1 pyramidal
Ca2+
185
Long term potentiation :Schaffer collateral
Because activity in the post synaptic cell (in this case CA1 pyramidal neuron) is required for this form of long term memory, it is considered to be a _____memory
Associative
186
Properties of long term potentiation:
The NMDA receptor endows longterm potentiation with distinct properties. What are they (3 of them)?
1. Cooperativity
2. Associativity
3. Specificity
187
Properties of long term potentiation:
What is cooperativity?
Because the activation of the NMDA receptor depends on the depolarization of the post synaptic neuron, the simultaneous but weak activation of multiple pre synaptic neurons can generate LTP
188
Properties of long term potentiation:
What is associativity?
The strong activation of one pre synaptic neuron together with weak activation of another pre synaptic neuron can generate long term potentiation
189
Properties of long term potentiation:
What is specificity?
LTP is only induced at active synapses
190
long term potentiation: hebb’s rule
What is hebb’s rule (theory of learning)?
When the axon of A excited cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells so that As efficiency at firing at B increases
In otherwords - neurons that fire together are more likely to be active with each other and wire together
191
Long term potentiation has 2 phases. What are they?
1. Early long term potentiation
2. Late long term potentiation
192
What is short term potentiation?
One train of action Potentials produces a phase of long term potentiation that can last 1 to 3 hours.
Early LTP does not require protein synthesis, PKA activation and gene transcription
193
What is late long term potentiation?
Many trains of action potentials produce a phase of of long term potentiation that can last 24 hours
Late LTP requires protein synthesis, PKA activation and gene transcription
194
Short LTP
In short LTP a ____ train of stimulation activates the NMDA receptor by an influx of Ca2+ which activates ______.
This in turn activates different ______
Single
Calmodulin
Second messengers
195
In late LTP, _____trains of stimulation bring about calmodulin activating an ______ which increases _____.
This activates _____ and eventually _____(the transcription factor regulating the effectors of LTP).
The maintenance of late LTP depends on an isoform of PKC called _____ which facilitates the insertion of AMPA receptors into the post synaptic membrane.
Many
Adenylyl cyclase
cAMP
PKA
CREB
PKM gamma
196
True/false: long term potentiation can be long lasting and can persist for days or weeks
True.
197
True/false: long term potentiation decreases synaptic efficiency between two neurons.
False. I
It increases synaptic transmission
198
True/false: there are different forms of long term potentiation observed in the hippocampus
True
199
True/false: synapses that do not contribute to the firing of a cell are weakened.
True
200
What are place cells?
neurons in the hippocampus that fire when an animal visits specific regions of its environment, called place fields, and are thought to provide the foundation for an internal representation of space, or 'cognitive map'
201
_____ and _____ neurons fire when an animal enters a specific place.
CA1 and CA3
