Unit 6

Question 1

Learning

Answer 1

is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. At the neural level, learning occurs through strengthening and weakening of specific synapses.

Question 2

Behaviorism

Answer 2

Behaviorism is a psychological field that seeks to explain how the behavior of humans and other animals develop through types of learning. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent (prior) stimuli in the environment [e.g., classical conditioning], or a consequence of that individual’s history, including especially reinforcement and punishment contingencies, together with the individual’s current motivational state and controlling stimuli [operant conditioning]. It was initially proposed by Watson. Although behaviorists now generally accept the important role of genetic heredity in determining behavior, they focus primarily on environmental events, usually in an experimental and/or laboratory setting.
 Finding ways to change behavior

Question 3

Psychoanalytic theory

Answer 3

Also known as depth psychology, psychoanalytic theory was developed by Freud, Jung, and Adler. For Freud, a central premise was thus that we are driven by unconscious wishes that we are unaware of, and this lack of awareness results in driven or self-defeating behavior. Freud believed we delude ourselves about reasons for our behaviors and this self-deception limits our choices. By becoming aware of our unconscious wishes and our defenses against them, we increase the choices available to us. Thus, as we decrease the extent to which we are driven by unconscious factors, we assume a greater degree of agency. This theory was not typically tested experimentally.

Question 4

Law of Effect

Answer 4

Any stimulus/action/context associated with positive reinforcement will tend to be repeated, while those that produce a discomforting or negative effect become less likely to occur again in that situation. This theory competed with Freud’s psychoanalysis-based “depth psychology,” which could not usually be tested experimentally. Developed by Thorndike in the late 1890s.

Question 5

Ethology

Answer 5

Ethology is the scientific and objective study of animal behavior, usually with a focus on behavior under natural conditions, and viewing behavior as an evolutionarily adaptive trait. This contrasts with behaviorism, which studies behavior under controlled, experimental settings.

Question 6

Classical conditioning

Answer 6

is a type of learning that had a major influence on behaviorism. Discovered by Russian physiologist Ivan Pavlov, classical conditioning is a learning process that occurs through associations between an environmental, neutral, unrelated stimulus and a naturally occurring, unconditioned stimulus. Applies to reflexive behaviors

Question 7

Higher order classical conditioning

Answer 7

A series of neutral stimuli that is happening close together in time can be associated with the behavioral response by conditioning them in stages

Question 8

Neutral stimulus

Answer 8

In classical conditioning, a neutral stimulus (NS) is a stimulus that initially does not evoke a response until it is paired with the unconditioned stimulus. For example, in Pavlov’s experiment the bell was the neutral stimulus, and only produced a response when it was paired with food.

Question 9

Unconditioned stimulus

Answer 9

In classical conditioning, the unconditioned stimulus is a stimulus that causes a natural and automatic unconditioned response. In Pavlov’s study, the unconditioned stimulus was food, which already made the dog salivate. [Note that salivation to food may have already been conditioned as a response when the dog was very young, but that was considered to be outside of the experimental setting and viewed as an instinct or reflex.]

Question 10

Unconditioned response:

Answer 10

In classical conditioning, an unconditioned response is an unlearned response that occurs automatically when the unconditioned stimulus is presented. Pavlov showed the existence of the unconditioned response by presenting a dog with a bowl of food and the measuring its salivary secretions

Question 11

Conditioned stimulus

Answer 11

In classical conditioning, the conditioned stimulus (CS) is a substitute stimulus that triggers the same response in an organism as an unconditioned stimulus. Simply put, a conditioned stimulus makes an organism react to something because it is associated with something else. For example, Pavlov’s dog learned to salivate at the sound of a bell.

Question 12

Conditioned response

Answer 12

In classical conditioning, the conditioned response (CR) is the learned response to the previously neutral stimulus. In Ivan Pavlov’s experiments in classical conditioning, the dog’s salivation was the conditioned response to the sound of a bell.

Question 13

Classical conditioning in humans

Answer 13

Person has a stomach bug (US) causing nausea (UR)
Person eats chocolate (NS)
Person vomits from stomach bug after eating chocolate (acquisition)
Person now feels disgust/nausea (CR) for chocolate (CS)

Question 14

Operant Conditioning

Answer 14

(sometimes referred to as instrumental conditioning) is a method of learning that employs rewards and punishments for behavior. Through operant conditioning and repeated experience, an association is made between a behavior and a consequence (whether negative or positive) for that behavior. The response is then increased or decreased. Applies to voluntary behaviors.
 Reward/reinforcement increases desired behavior
 Punishment decreases behavior

Question 15

Skinner’s classic pigeon experiment: operant conditioning

Answer 15

1) Pigeon presented with colored dot (stimulus)
2) Pigeon pecks dot (response)
3) Pigeon receives food (Pos. reinforcement)
Pigeon learns association that pecking dot predicts food
Key: food reward must occur immediately after the peck in order for association to be learned

Question 16

Reinforcement

Answer 16

is a term used in operant conditioning to refer to anything that increases the likelihood that a response will occur. Reinforcement can include anything that strengthens or increases a behavior, including specific tangible rewards, events, and situations. Primary reinforcements occur naturally and tend to have an evolutionary basis in that they aid in the survival of the species (e.g., air, food, sleep, sex, water). Secondary reinforcements involve stimuli that have become rewarding by being paired with another reinforcing stimulus

Question 17

Positive reinforcement

Answer 17

adds something to increase desired `response/behavior

Question 18

Negative reinforcement

Answer 18

removes something in order to increase desired response/behavior

Question 19

Punishment

Answer 19

is a term used in operant conditioning to refer to any change that occurs after a behavior that reduces the likelihood that that behavior will occur again in the future. While positive and negative reinforcements are used to increase behaviors, punishment is focused on reducing or eliminating unwanted behaviors. The difference: Reinforcement increases the chances that a behavior will occur and punishment decreases the chances that a behavior will occur.

Question 20

Positive punishment

Answer 20

involves presenting an aversive stimulus after a behavior has occurred in order to decrease that behavior.

Question 21

Negative punishment

Answer 21

involves taking away a desirable stimulus after a behavior has
occurred in order to decrease that behavior.

Question 22

Reinforcement schedules

Answer 22

In situations when present reinforcement is controlled, such as during training, the timing of when a reinforcer is presented can be manipulated. During the early stages of learning, continuous reinforcement is often used, such as when you first teach your dog a new trick. However, during later stages of learning, variable partial reinforcements tend to lead to a fast response rate and slow extinction rate.

Question 23

Continuous Reinforcement

Answer 23

This schedule involves reinforcing a response each and every time it occurs. Learning tends to occur relatively quickly, yet the response rate is quite low. Extinction also occurs very quickly once reinforcement is halted.

Question 24

Partial Reinforcement

Answer 24

Once a behavior has been acquired, it’s often a good idea to switch to a partial reinforcement schedule. The four main types of partial reinforcement include: Fixed interval, fixed ratio, variable interval and variable ratio

Question 25

Fixed-interval schedules

Answer 25

Reinforcing a behavior after a specific period of time has elapsed. Response rates remain fairly steady and start to increase as the reinforcement time draws near, but slow immediately after the reinforcement has been delivered.

Question 26

Fixed-ratio schedules

Answer 26

Reinforcing a behavior after a specific number of responses have occurred. This typically leads to a fairly steady response rate.

Question 27

Variable-interval schedules

Answer 27

Reinforcing the behavior after an unpredictable period of time has elapsed. This tends to lead to a fast response rate and slow extinction rate.

Question 28

Variable-ratio schedules

Answer 28

Reinforcing the behavior after an unpredictable number of responses. This also leads to both a high response rate and slow extinction rates.

Question 29

Acquisition

Answer 29

apply to both classical and operant conditioning: In the initial period of learning, acquisition describes when an organism learns to connect a neutral stimulus and an unconditioned stimulus.

Question 30

Extinction

Answer 30

apply to both classical and operant conditioning: In psychology, extinction refers to gradual weakening of a conditioned response by breaking the association between the conditioned and the unconditioned stimuli. For example, when the bell was repeatedly rung and no food presented Pavlov’s dog gradually stopped salivating at the sound of the bell.

Question 31

Spontaneous recovery

Answer 31

apply to both classical and operant conditioning: Spontaneous Recovery is a phenomenon of Pavlovian conditioning that refers to the return of a conditioned response (in a weaker form) after a period of time following extinction. For example, when Pavlov waited a few days after extinguishing the conditioned response, and then rang the bell once more, the dog salivated again.

Question 32

Generalization

Answer 32

apply to both classical and operant conditioning: In psychology, generalization is the tendency to respond in the same way to stimuli that are similar but not identical to the conditioned stimulus. For example, in Pavlov's experiment, if a dog is conditioned to salivate at the sound of a bell, it may later salivate to a higher pitched bell.

Question 33

Discrimination

Answer 33

apply to both classical and operant conditioning: In classical conditioning, discrimination is a process through which individuals learn to differentiate among similar stimuli and respond appropriately to each one. For example, eventually Pavlov’s dog learns the difference between the sounds of the 2 bells and no longer salivates at the sound of the non-food bell.

Question 34

Temporal contiguity

Answer 34

occurs when two stimuli are experienced close together in time and, as a result, an association may be formed. The repeated co-activation of circuits increases the likelihood that if one of those circuits is activated the other will also activate (Circuits that fire together, wire together). In Pavlovian conditioning the strength of the association between the conditioned stimulus (CS) and the unconditioned stimulus (US) is largely affected by temporal contiguity. If the CS and UC are too far apart in time, no association will be made.

Question 35

Hebbian theory

Answer 35

is a neuroscientific theory based on the idea that an increase in synaptic efficacy arises from a presynaptic cell's repeated and persistent stimulation of a postsynaptic cell. It is an attempt to explain synaptic plasticity, the adaptation of brain neurons during the learning process

Question 36

Synaptogenesis/Dendritization

Answer 36

 Increase in number of dendritic branches (more surface area for more receptors to increase chance of AP)

Question 37

Hebbian synapse

Answer 37

is a junction between neurons that is strengthened when it successfully fires the postsynaptic cell.

Question 38

Long-term potentiation (LTP)

Answer 38

is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies learning and memory. One of the key indicators of LTP induction is the increase in the ratio of AMPAR to NMDARs following high-frequency stimulation. The idea is that AMPARs are trafficked from the dendrite into the synapse and incorporated through some series of signaling cascades. Long term potentiation leads to the increased likelihood of a neuronal response (AP) along repeatedly co-activated circuits in post synaptic cell

Question 39

LTP Process

Answer 39

Glutamate binds to postsynaptic AMPARs and another glutamate binds the NMDAR. Ligand binding causes the AMPARs to open, and Na+ flows into the postsynaptic cell, resulting in a depolarization. NMDARs, on the other hand, do not open directly because their pores are occluded at resting membrane potential by Mg2+ ions (Mg++ blocks ion gates). NMDARs can open only when a depolarization from the AMPAR activation leads to Mg2+ cation being kicked out into the extracellular space, allowing the pore to pass current. Unlike AMPARs, however, NMDARs are permeable to both Na+ and Ca2+. The Ca2+ that enters the cell triggers the upregulation of AMPARs to the membrane, which results in a long-lasting increase in EPSP size underlying LTP. The calcium entry also phosphorylates the enzyme CaMKII, which phosphorylates AMPARs, increasing their single-channel conductance. Prolonged activity along the circuit leads to other structural changes such as building new dendritic branches.

Question 40

AMPA receptors (AMPARs)

Answer 40

is an ionotropic transmembrane receptor for glutamate that mediates fast synaptic transmission in the central nervous system. It is permeable to Na+ and K+, meaning it allows those ions to enter the cell after its channel opens when it binds to the excitatory neurotransmitter, glutamate. Its name is derived from its ability to be activated by the artificial glutamate analog ‘AMPA’. AMPARs have been shown to play an integral role in the process of LTP.

Question 41

NMDA receptors (NMDARs)

Answer 41

are glutamate-gated cation channels with sodium and high calcium permeability that play important roles in many aspects of the biology of higher organisms. They are critical for the development of the central nervous system (CNS), generation of rhythms for breathing and locomotion, and the processes underlying learning, memory, and neuroplasticity/LTP.

Question 42

Dendritic spine morphology

Answer 42

Shapes of spines include a range of sizes and in a variety of shapes, commonly classified as thin, stubby and mushroom. Why is the morphology of spines important? There is strong correlation between the size of the spine head and the strength of the synapse, presumably related to the higher levels of AMPA receptors in larger spines. There is also evidence that it is the smaller weaker spines that preferentially undergo long-term potentiation (LTP), whereas larger spines are more stable and show less plasticity. Such observations have led to the idea that thin spines might represent ‘plasticity spines’ and large mushrooms ‘memory’ spines.

Question 43

Actin cytoskeleton

Answer 43

is a network of actin and actin binding proteins that together with the other components of the cytoskeleton such as microtubules and intermediate filaments is responsible for essential cellular processes like spine morphology, cell migration, axonal growth, phagocytosis, cytoplasmic streaming and organelle transport.

Question 44

Actin

Answer 44

Added to the spine in the dendrite to widen synaptic surface, strengthening the spine

Question 45

LTP: retrograde sig to presynaptic cell

Answer 45

Recall  During brain dev. post synaptic cells release chemical feedback, promoting further pre synaptic activity  After birth in most circuits NT's are only released by pre synaptic cells

Question 46

LTP: Perforation

Answer 46

Increases synaptic number  Cellular correlation  Increases independent synaptic release sites  Increases transmission

Question 47

Neural backpropagation

Answer 47

is the phenomenon in which after the action potential of a neuron creates a voltage spike down the axon (normal propagation) another impulse is generated from the soma (cell body) and propagates toward to the apical (top) portions of the dendritic arbor or dendrites, from which much of the original input current originated. In addition to active backpropagation of the action potential, there is also passive electrotonic spread (the passive spread of charge inside a neuron). While there is ample evidence to prove the existence of back-propagating action potentials, the function of such action potentials and the extent to which they invade the most distal dendrites remains highly controversial. There is growing evidence that back-propagating action potentials contribute to LTP, such as through the development of new spines.

Question 48

Long-term depression (LDT)

Answer 48

is essentially the reverse of LTP and serves to produce a long-lasting decrease in synaptic strength. LTD is one of several processes that serves to selectively weaken specific synapses in order to make constructive use of synaptic strengthening caused by LTP. This is necessary because, if allowed to continue increasing in strength, synapses would ultimately reach a ceiling level of efficiency, which would inhibit the encoding of new information. LTD in the hippocampus and cerebellum have been the best characterized, but there are other brain areas in which mechanisms of LTD are understood. LTD has also been found to occur in different types of neurons that release various neurotransmitters, however, the most common neurotransmitter involved in LTD is L-glutamate via NMDA receptors.

Question 49

LTP vs LTD

Answer 49

LTP  AMPA receptors and NMDA receptors get an influx of Ca++ through them activating enzymes and kinases causing exocytosis or pushes out AMPA receptor into cell membrane.  The protein molecules diffuses through the membrane and over the synaptic cleft which makes the synaptic spine bigger for more receptors. LTD  Endocytosis where a low scale influx of Ca++ changes certain enzymes to be activated that drive bilateral movement of AMPA receptors back to the zone.  AMPA receptor get's taken back into the cell and stored  Turns down signal and decreases shape and spine may go away  Number of receptors goes down

Question 50

Metaplasticity

Answer 50

refers to the amount of plasticity (the plasticity of synaptic plasticity). The prior history of synaptic activity is an additional variable that influences the synaptic state, and thereby the degree, of LTP or LTD produced by a given experimental protocol. In a sense, then, synaptic plasticity is governed by an activity-dependent plasticity of the synaptic state; such plasticity of synaptic plasticity has been termed metaplasticity. Allows the neurons to maintain a functional range of neuronal outputs that is affected by overall synaptic inhibition in the region, current hormone lvs, etc

Question 51

Synaptic scaling (or homeostatic scaling)

Answer 51

is a form of homeostatic (optimal, steady-state functioning) plasticity, in which the brain responds to chronically elevated activity in a neural circuit with negative feedback, allowing individual neurons to reduce their overall action potential firing rate and maintain a functional range of neuronal outputs. Where Hebbian plasticity mechanisms (LTP, LTD) modify neural synaptic connections selectively, synaptic scaling normalizes all neural synaptic connections by decreasing the strength of each synapse by the same factor (multiplicative change), so that the relative synaptic weighting of each synapse is preserved.

Question 52

Memory

Answer 52

an organism's mental ability to store, retain and recall info o Encoding or registration: attend to or maintain current sensory or internal info o Storage: create permanent record of encoded info o Retrieval or recall: bring back stored information in response to some cue

Question 53

Short term (working) memory

Answer 53

 limited, active, transient traces of experiences that happened in the very recent past (no longer than a few seconds ago). It's the "RAM" of human memory. Lasts about 2 second without rehearsal, but can be maintained with rehearsal. Visual working memory is limited to about 3-4 objects.  There is an even shorter type of memory called sensory memory or the sensory trace, which operates on the order of msec. Information from sensory memory is only transferred into short-term/working memory if you attend to that particular incoming sensory information.

Question 54

Long-term memory (LTM)

Answer 54

is the stage of the dual memory model proposed by the Atkinson Shiffrin memory model in which informative knowledge can be stored for long periods of time. While short-term and working memory persist for only about 18 to 30 seconds, informative knowledge can remain as long-term memory indefinitely. Long-term memory is commonly labelled as explicit memory (declarative), as well as episodic memory, semantic memory, autobiographical memory, and implicit memory (procedural memory).

Question 55

Declarative memory

Answer 55

consists of facts and events that can be consciously recalled or "declared." Also known as explicit memory, it is based on the concept that this type of memory consists of information that can be explicitly stored and retrieved. Declarative memory subtypes include episodic memory (events) and semantic memory (facts, concepts).

Question 56

Regions involved in declarative memory

Answer 56

Prefrontal cortex  Memory for facts, abstract rules, episodic memory especially life experiences  Working (short term memory)  Planning complex cognitive behaviors, decision making, personality expression, moderating correct social behavior, orchestration of thoughts/actions in accordance with internal goals Medio Dorsal Thalamus  Rapid integration of new learning; executive functions with PFC Hippocampus  Memory consolidation and retrieval  LTP and LTD

Question 57

Semantic memory

Answer 57

Factual knowledge independent of time and place

Question 58

Episodic memory

Answer 58

Theoretical knowledge of a specific moment in time and place

Question 59

Procedural memory

Answer 59

is a part of the long-term memory that is responsible for knowing how to do things, also known as motor skills. As the name implies, procedural memory stores information on how to perform certain procedures, such as walking, talking and riding a bike. It is typically acquired through repetition and practice, sometimes described as muscle memory or body memory. Delving into something in your procedural memory does not involve conscious thought. Procedural memory is a subset of implicit memory, sometimes referred to as unconscious memory or automatic memory. Implicit memory uses past experiences to remember things without thinking about them. It differs from declarative memory, or explicit memory, which consists of facts and events that can be explicitly stored and consciously recalled or "declared." Located in  Cerebellum, basal ganglia

Question 60

Rat explores a maze until it learns some regularity predicting the placement of food. As long as the the floor is rough they continue forward then turn right. Their actions are based on sensory cues, what type of memory is used

Answer 60

Procedural Damage to the cerebellum impairs this

Question 61

Rat explores a maze until it learns some regularity predicting the placement of food. They go to the same area where they found food in the last trial. Their actions are based on rules what type of memory is used

Answer 61

Declarative Damage to hippocampus impairs this

Question 62

Procedural memory: conditioned eye blink

Answer 62

Rabbits have an eye blink reflex  A puff of air to the eye results in an eye blink (UR)  Bell is rung, paired with the puff of air repeatedly  Eventually when the rabbit hears the bell it will blink anticipating the puff  It has learned classical conditioning If the suppress (cool) LIP of cerebellum the subject doesn't blink (reflex is temp disabled)  Doesn't learn association If suppress (cool) Red Nucleus rabbit doesn't blink  Red nucleus can't send signal to eye muscles  If red nucleus warms again the rabbit blinks to bell showing it has learned  Cerebellum is primarily responsible for procedural learning

Question 63

Memories are stored in distributed, neocortical networks

Answer 63

These networks can hold episodic memories of specific events and their contextual details, or semantic memories that comprise factual knowledge about the world, concepts, or rules. The defining features of these different memory types are thought to be encoded in modality-specific, posterior representational regions (e.g., auditory or visual sensory association cortices). Yet, as we remember, we reconstruct memories as a whole. The so-called “binding problem” describes the need to converge and integrate information from different storage sites. Presumably, this “binding” underlies memory retrieval, but also the holistic experience of present percepts, and it might be achieved in twosteps. First, neuronal synchronization between distant brain regions has been proposed as a functional mechanism for the integration of information. Second, higher-level association regions are assumed to support feature convergence.

Question 64

Sensory Memory

Answer 64

sensory memory or the sensory trace, which operates on the order of msec. Information from sensory memory is only transferred into short-term/working memory if you attend to that particular incoming sensory information.

Question 65

Prefrontal cortex (PFC)

Answer 65

comprises parts of the frontal lobe anterior to the motor regions. The functions of the PFC include working memory and executive functions. These behaviors involve the ability to project future consequences resulting from current actions, the choice between good and bad actions (or better and best) (also known as conscience), the override and suppression of socially unacceptable responses, and the determination of similarities and differences between things or events. The PFC also plays an important part in integrating longer non-task-based memories stored across the brain(i.e., not procedural memories). These are often memories associated with emotions derived from input from the brain's limbic system. PFC processing may modify those emotions to generally fit socially acceptable norms. Psychological tests that measure PFC function include delayed match-to-same task, the Wisconsin Card Sorting Test, and measures of language and numeracy skills.

Question 66

Thalamus

Answer 66

a small structure within the brain located just above the brain stem between the cerebral cortex and the midbrain and has extensive nerve connections to both. The primary function of the thalamus is to relay motor and sensory signals to the cerebral cortex. It also regulates sleep, alertness, and wakefulness. Emerging evidence further suggests that the thalamus plays a role in learning and decision-making.

Question 67

Korsakoff's syndrome

Answer 67

an irreversible syndrome characterized by abnormal eye movements, loss of coordination, tremors, confusion, confabulation, apathy, and severe anterograde and some retrograde memory impairment. It is usually caused by vitamin deficiency in alcoholism, or lesions to thalamus and mammillary bodies

Question 68

Declarative memory test

Answer 68

1) Subject views the initial image and then must select matches of subsequent images based on unknown categories 2) Positive feedback shows that this image is a correct match 3) Negative feedback on other trials demonstrates the same rule and the subject learns the rule after a certain number of tries If lesion happens to hippocampus after animal has learned rule performance is impaired showing hippocampus plays a role in forming and retrieving memories

Question 69

Anterograde amnesia

Answer 69

memory loss where new events are not stored in long term memory (patient examples are H.M., Clive Wearing, and N.A.). H.M. has a small amount of retrograde amnesia (loss of prior memory), as well, affecting the time right before his surgery.

Question 70

Mediodorsal nucleus of the thalamus (MD)

Answer 70

has been implicated in executive functions (such as planning, cognitive control, working memory, and decision-making) and during rapid integration of new learning. MD has significant interconnectivity with the prefrontal cortex (PFC). The thalamic MD has extensive excitatory cortico-thalamo-cortical connections, especially with the PFC. MD also receives modulatory inputs from forebrain, midbrain and brainstem regions. Current evidence suggests the MD is particularly important during rapid trial-by-trial associative learning and decision making paradigms that involve multiple cognitive processes.

Question 71

Match-to-sample tasks

Answer 71

are behavioral experiments developed during the era of behaviorism, and were described by B.F. Skinner, among others. In its early form, a pigeon would be presented with a colored light stimulus sample. It would then proceed to peck the sample and then be presented with two comparison stimuli. One comparison stimulus matches the sample (either because it is an identical color or because the animal has learned an association such as green means left) and the other does not match. If it chooses (pecks) the matching comparison, then it is rewarded. Variations of this task are used in humans, especially to study working memory and executive function in the frontal lobe.

Question 72

Limbic system

Answer 72

a set of brain structures located on both sides of the thalamus, immediately beneath the cerebrum. It is not a separate system but a collection of structures from the telencephalon, diencephalon, and mesencephalon. The limbic system supports a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction. Emotional life is largely housed in the limbic system, and it has a great deal to do with the formation of memories.

Question 73

Hippocampus

Answer 73

a neural structure in the medial temporal lobe of the brain that has a distinctive, curved shape that has been likened to the sea-horse monster of Greek mythology and the ram's horns of Amun in Egyptian mythology. It has major roles in learning and memory. Has a function in episodic memory  Involved in pathway for declarative memory  Key for memory consolidation  Damage = anterograde amnesia, some retrograde Has a function in spatial navigation  Place cells: tuned for particular location or head/travel direction

Question 74

Hippocampus internal structure

Answer 74

Hippocampal formation  Dentate gyrus  Subiculum  The Cornu Ammonis fields (CA1-CA3)  CA-4 is considered part of the dentate gyrus  CA1-CA3 fields = the hippocampus proper

Question 75

Dentate gyrus

Answer 75

part of the hippocampus and/or hippocampal formation (depending on naming scheme) that receives the primary inputs to the hippocampus from the entorhinal cortex. The dentate gyrus is thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments, possible role in memory of the differences that make each place unique and other functions. It also regulates mood; happiness, possible role in depression. It is notable as being one of a select few brain structures currently known to have high rates of neurogenesis in adult rats (other sites include the olfactory bulb and cerebellum). It may also play a role in mood regulation.

Question 76

Dente gyrus structure

Answer 76

 Contains granule cells, the principal excitatory neurons of the dentate gyrus  Input = perforant pathway from entorhinal cortex  No direct inputs from other cortical structures, it's all throughout the perforant pathway  Output = mossy fiber pathway  Projects mostly to the interneurons of the CA3 subfield, also to pyramidal cells

Question 77

Cornu Ammonis fields, CA1-CA3

Answer 77

(cornu ammonis = ram’s horns of Amun = CA): subregions of the hippocampus that each have specific cells types and connections. CA4, “the hilus,” is considered part of the dentate gyrus.

Question 78

Subiculum

Answer 78

(Latin for "support") is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper. It serves as the main output for the hippocampus, and get's input from CA1 and entorhinal cortical layer III pyramidal neurons  Projects to: nucleus accumbens, septal nuclei, prefrontal cortex and amygdala  Pyramidal neurons in subiculum transition between two modes of action potential output: bursting and single spiking  Thought to be important for routing information out of the hippocampus Function  Role in working memory, drug addiction, temporal lobe epilepsy

Question 79

Long term memory storage

Answer 79

Declarative memories are not stored in hippocampus, thalamus, or prefrontal cortex Those circuits are required for consolidation and retrieval of information stored elsewhere in the cortex Memories are stored in distributed, neocortical networks Lateral Occipital cortex  Involved in visual memory object recognition  Damage here causes visual agnosia: inability to recognize objects by sight Fusiform Gyrus  Involved in visual memory for faces Damage here causes prosopagnosia: face blindness Dorsal temporal cortex - Wernicke's area  Involved in auditory memory for sound/work/language recognition  Damage here causes Wernicke's aphasia: inability to comprehend spoken language Posterior parietal cortex  Involved in memory for space from an egocentric (self-centered) frame of reference  Damage here causes problems with visuospatial processing, sensorimotor integration and attention/working memory

Question 80

Damage to posterior hippocampus can affect

Answer 80

 Navigation, map reading, location memory

Question 81

Pathways through hippocampal formation

Answer 81

Information flows into the hippocampus at dentate gyrus then through the CA subfields and then out to the subiculum.

Question 82

Hippocampal pathway Perforant path:

Answer 82

INPUT – from entorhinal cortex primarily to dentate gyrus and CA3; also to CA1 and subiculum; site of LTP discovery

Question 83

Hippocampal pathway Mossy fiber pathway

Answer 83

1) INTERNAL connections – from granule cells of dentate gyrus to CA3; Specialized LTP (NMDA –independent) found here

Question 84

Hippocampal pathway Schaffer collaterals

Answer 84

2) INTERNAL connections – from CA3 to CA1; classic NMDA dependent LTP/LTD occurs here

Question 85

Hippocampal pathway CA1 to subiculum to entorhinal cortex

Answer 85

OUTPUT – follows strict anatomical connections; reciprocal feedback loop returns from EC to sub to CA1

Question 86

Medial temporal lobe (MTL)

Answer 86

the middle, inner section of the temporal lobe where much of the limbic system resides. Regions in the MTL that neighbor the hippocampus include the parahippocampal cortex, the entorhinal cortex, and the perirhinal cortex.

Question 87

Parahippocampal cortex (PHC)

Answer 87

an MTL region that surrounds the hippocampus and is part of the limbic system. This region plays an important role in memory encoding and retrieval.

Question 88

Entorhinal cortex (EC)

Answer 88

an MTL region that functions as a hub in a widespread network for memory and navigation. The EC is the main interface between the hippocampus and neocortex. The EC-hippocampus system plays an important role in declarative (autobiographical/episodic/semantic) memories and in particular spatial memories including memory formation, memory consolidation, and memory optimization in sleep. The EC is also responsible for the pre-processing (familiarity) of the input signals in the reflex nictitating membrane response of classical trace conditioning, the association of impulses from the eye and the ear occurs in the entorhinal cortex.

Question 89

Perirhinal cortex

Answer 89

an MTL region that receives highly processed sensory information from all sensory regions, and is generally accepted to be an important region for memory.

Question 90

Spatial Memory

Answer 90

Knowledge of different locations as well as the spatial relationships among objects. The posterior hippocampus is thought to store information about allocentric (viewpoint independent) space.

Question 91

Place cells

Answer 91

specialized neurons of the hippocampus involved in forming (and storing?) spatial memories. These fire when an animal enters a particular place in its environment, which is known as the place field. Place cells are thought, collectively, to act as a cognitive representation of a specific location in space, known as a cognitive map.

Question 92

Grid cells

Answer 92

specialized neurons of the entorhinal cortex that are also involved in spatial memory. They fire when the animal is in any of multiple locations that form a regular grid across the environment.

Question 93

Other cell types

Answer 93

include conjunctive grid cells (these fire only when the animal is on a vertex of the grid and when the animal moves in a particular direction), head-direction cells, speed cells, and boundary vector cells. The lateral entorhinal cortex (LEC) also provides input to the hippocampus and contains cells that carry sensory information about the current position.

Question 94

Eye-blink conditioning (EBC)

Answer 94

is a form of classical conditioning that has been used extensively to study neural structures and mechanisms that underlie learning and memory. The procedure is relatively simple and usually consists of pairing an auditory or visual stimulus (the conditioned stimulus (CS)) with an eyeblink-eliciting unconditioned stimulus (US) (e.g. a mild puff of air to the cornea or a mild shock). Naïve organisms initially produce a reflexive, unconditioned response (UR) (e.g. blink or extension of nictitating membrane) that follows US onset. After many CS-US pairings, an association is formed such that a learned blink, or conditioned response (CR), occurs and precedes US onset. The magnitude of learning is generally gauged by the percentage of all paired CS-US trials that result in a CR. Under optimal conditions, well-trained animals produce a high percentage of CRs (> 90%).

Question 95

corneal blink reflex

Answer 95

is caused by a loop between the trigeminal sensory cranial nerve (CN V) and the facial motor cranial nerve (CN VII) innervation of the orbicularis oculi muscles, the muscles that close the eye. The reflex activates when a sensory stimulus contacts either free nerve endings (pain) or mechanoreceptors (touch) within the epithelium of the cornea.

Question 96

Red nucleus

Answer 96

a large structure located centrally within the tegmentum that is involved in the coordination of sensorimotor information.

Question 97

Cerebellum

Answer 97

(Latin for “little brain”) a major structure of the hindbrain that is located near the brainstem. This part of the brain is responsible for coordinating voluntary movements. It is also responsible for a number of functions including motor skills such as balance, coordination, and posture.

Question 98

Basal ganglia

Answer 98

a group of subcortical nuclei, of varied origin, in the brains of vertebrates. When it refers to structures in the central nervous system, “ganglia” is a term that refers to a group of cell bodies (also called nuclei) outside of the cortical sheet (the cell bodies that make up the gray matter along the sulci and gyri). The basal ganglia are situated at the base of the forebrain (hence, “basal”) and on top of the midbrain. The components of the basal ganglia are strongly interconnected with the cerebral cortex, thalamus, brainstem, and cerebellum. The basal ganglia are associated with a variety of functions, including control of voluntary motor movements, procedural learning, habit learning, eye movements, cognition, and emotion.

Question 99

Tower of Hanoi

Answer 99

a mathematical game or puzzle commonly used to test procedural memory and executive function. It consists of three rods and a number of disks of different sizes, which can slide onto any rod. The puzzle starts with the disks in a neat stack in ascending order of size on one rod, the smallest at the top, thus making a conical shape. The objective of the puzzle is to move the entire stack to last rod, obeying a set of simple rules. Patients with amnesia (affecting declarative memory, like H.M.) can improve their efficiency at completing the puzzle over multiple trials (procedural memory intact) despite not remembering ever seeing the puzzle before (declarative memory impaired).