Learning and Memory

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Learning and Memory

• Mind and Brain

• Chapter 13

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• You are responsible for Chapter 13 (text and
  notes) for you final as well as all other
  chapters (and notes) covered in class.

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• http//www.youtube.com/watch?vJliczINA__Yfeature
  related

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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The Nature of Learning

• Introduction
• Learning refers to the process by which
  experiences change our nervous system and hence
  our behavior we refer to these changes as
  memories
• Experiences are not stored they change the way
  we perceive, perform, think, and plan
• They do so by physically changing the structure
  of the nervous system, altering neural circuits
  that participate in perceiving, performing,
  thinking and planning.

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The Nature of Learning

• Learning can take at least 4 basic forms
• Perceptual Learning
• Stimulus-Response Learning
• Classical Conditioning
• Instrumental Conditioning
• Motor Learning
• Relational Learning

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The Nature of Learning

• Perceptual Learning
• Learning to recognize a particular stimulus
• Primary function ability to identify and
  categorize objects and situations
• Each sensory system is capable of perceptual
  learning
• Accomplished by changes in the sensory
  association cortex

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The Nature of Learning

• Stimulus-Response Learning
• Learning to automatically make a particular
  response in the presence of a particular stimulus
  
• Involves the establishment of connections between
  circuits involved in perception and those
  involved in movement
• Classical conditioning
• Instrumental conditioning

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The Nature of Learning

• Classical Conditioning
• Unconditional Stimulus (US) stimulus that
  produces a defensive or appetitive response.
• Unconditional Response (UR) response to the US.
• Conditional Stimulus (CS) stimulus, which when
  paired with the US during training, comes to
  elicit a learned response.
• Conditional Response (CR) response to the
  presentation of the CS.

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Figure 13.1 A Simple Neural Model of Classical
Conditioning
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The Nature of Learning

• Hebb Rule
• hypothesis proposed by Donald Hebb that the
  cellular basis of learning involves strengthening
  of a synapse that is repeatedly active when the
  postsynaptic neuron fires.

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Figure 13.1 A Simple Neural Model of Classical
Conditioning
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The Nature of Learning

• Instrumental Conditioning (Operant conditioning)
• learning procedure whereby the effects of a
  particular behavior in a particular situation
  increase (reinforce) or decrease (punish) the
  probability of the behavior.
• Reinforcing Stimulus appetitive stimulus that
  follows a particular behavior and thus makes the
  behavior become more frequent.
• Punishing Stimulus aversive stimulus that
  follows a particular behavior and thus makes the
  behavior become less frequent.
• CC involves automatic or species-typical
  responses, but OC involves behaviors that have to
  be learned
• CC involves an association between 2 stimuli, OC
  involves an association between a response and a
  stimulus.
• OC is considered more flexible because it permits
  an organism to adjust its behavior according to
  the consequences of that behavior.

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Figure 13.2 A Simple Neural Model of Instrumental
Conditioning
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The Nature of Learning

• Motor Learning
• Learning to make a new response
• Component of stimulus-response learning

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Figure 13.3 An Overview of Perceptual,
Stimulus-Response (S-R), and Motor Learning.
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The Nature of Learning

• Relational Learning
• More complex form of learning
• Involves learning the relationships among
  individual stimuli
• Includes the ability to recognize objects through
  more than one sensory modality
• Involves learning the relative location of
  objects in the environment spatial learning
• Remembering the sequence in which events occurred
  during particular episodes episodic learning
• Hippocampus

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Electrical stimulation of circuits within the
  hippocampus can lead to long-term synaptic
  changes that seem to be responsible for learning
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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See Figure 13.4

• Primary input to the HF comes from the EC
• Axons of EC neurons pass through the perforant
  path and synapse with granule cells in the DG
• From these cells, the mossy fibers project to the
  pyramidal cells in CA3
• From CA3, Schaffer collaterals project to CA1
  cells
• The 3 synapses know as the trisynaptic loop

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Induction of LTP

• A stimulating electrode is placed in the PP and a
  recording electrode is placed in the DG
• A single pulse of electrical stimulation is
  delivered to the PP and the resulting population
  EPSP is recorded in the DG
• Population EPSP is the evoked potential that
  represents EPSPs of a population of neurons.
• LTP can be induced by stimulating the PP axons
  with a burst of electrical pulses (i.e., 100)
  within a few seconds

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LTP
The size of the first population EPSP tells us
the strength of the synaptic connections before
LTP is induced Evidence that LTP has occurred is
obtained by periodically delivering a single
pulse and then measuring the response in the DG
to see if it is bigger than the original response
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Synaptic Plasticity LTP and LTD

• LTP
• Can be induced in other parts of the HF and in
  other brain regions
• Can last for several months
• Can be induced in slices and in living animals
• Can follow the Hebb Rule (in slices)
• Associative Long-Term Potentiation long-term
  potentiation in which concurrent stimulation of
  weak and strong synapses to a given neuron
  strengthens the weak ones.

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Figure 13.6 Associative Long-Term Potentiation
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Figure 13.7 The Role of Summation in Long-Term
Potentiation

• Nonassociative LTP requires an additive effect
• Series of pulses delivered at high rate will
  produce LTP
• Same of pulses given at slow rate will not
  (LTD)
• Rapid rate of stimulation causes EPSPs to summate
• Rapid stimulation depolarizes the postsynaptic
  membrane more than slow stimulation

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Figure 13.8 Long-Term Potentiation

• Experiments have shown that synaptic
  strengthening occurs when NTS binds with
  postsynaptic receptors located in a dendrite that
  is already depolarized
• LTP requires 2 events
• Activation of synapses
• Depolarization of the postsynaptic membrane

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Synaptic Plasticity LTP and LTD

• Role of NMDA Receptors
• NMDA Receptor specialized ionotropic glutamate
  receptor that controls a calcium channel that is
  normally blocked by Mg2 ions.
• Calcium ions enter the cells through channels
  controlled by NMDA receptors only when glutamate
  is present and the postsynaptic membrane is
  depolarized

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Figure 13.9 The NMDA Receptor
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Synaptic Plasticity LTP and LTD

• Role of NMDA Receptors
• AP5 2-amino-5-phosphonopentanoate, a drug that
  blocks NMDA receptors.
• Blocks the establishment of LTP

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Synaptic Plasticity LTP and LTD

• Need glutamate depolarization.but how do
  dendrites become depolarized if only axons can
  produce action potential?
• Dendritic Spike action potential that occurs in
  the dendrite of some types of pyramidal cells.
• Threshold for activation is very high
• Only occurs when action potential is triggered in
  the axon
• Backwash of depolarization across cell body
  triggers dendritic spike
• Whenever the axon of a pyramidal cell fires, all
  of its dendritic spines become depolarized for a
  brief time.

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Synaptic Plasticity LTP and LTD

• Simultaneous occurrence of synaptic activation
  and a dendritic spike strengthens the active
  synapse.
• Magee and Johnston (1997) injected individual CA1
  pyramidal cells in hippocampal slices with a
  fluorescent dye that permitted them to see the
  influx of calcium
• When individual synapses became active at the
  same time that a dendritic spike had been
  triggered, Ca hot spots occurred near the
  activated synapses
• Size of EPSPs produced by these activated
  synapses became larger synapse became
  strengthened
• TTX (blocks Na current) injected near dendrite
  prevented dendritic spikes, no LTP!

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Synaptic Plasticity LTP and LTD

• Role of NMDA receptors in Associative LTP
• If weak synapses are active by themselves,
  nothing happens (NMDA receptors dont open)
• However, if the activity of strong synapses
  located elsewhere on the postsynaptic cell has
  caused the cell to fire, then a dendritic spike
  will depolarize the postsynaptic membrane enough
  to eject Mg ions from the Ca channels (of NMDA
  receptor)
• If some synapses then become active, Ca will
  enter the dendritic spines and cause the synapses
  to become strengthened

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Synaptic Plasticity LTP and LTD

• What is responsible for the increase in synaptic
  strength that occurs during LTP?
• Dendrites on CA1 neurons contain 2 types of
  glutamate receptors NMDA and AMPA

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Synaptic Plasticity LTP and LTD

• Mechanisms of Synaptic Plasticity
• AMPA Receptors ionotropic glutamate receptor
  that controls a sodium channel when open it
  produces EPSPs.
• Strengthening of individual synapses is
  accomplished by the insertion of more AMPA
  receptors into the postsynaptic membrane of the
  dendritic spine
• CaM-KII type of calcium-calmodulin kinase, an
  enzyme that must be activated by calcium may
  play a role in the establishment of LTP.
• Nitric Oxide Synthase enzyme responsible for
  the production of nitric oxide.
• Drugs that block this enzyme prevent the
  establishment of LTP in CA1

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Figure 13.16 Chemistry of LTP

• Activation of terminal button releases glutamate,
  which binds with NMDA receptors in the
  postsynaptic membrane of the dendritic spine
• If the membrane was depolarized by a dendritic
  spike, then calcium ions enter and activate
  CAM-KII
• CAM-KII travels to the postsynaptic density and
  causes the insertion of AMPA receptors
• LTP also initiates changes in synaptic structure
  and production of new synapses

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Figure 13.16 Chemistry of LTP

• The entry of calcium also activates NO synthase
• This produces NO which diffuses out of the
  dendritic spine and back to the terminal button
• The NO may then trigger chemical reactions that
  increase the release of glutamate
• Long-lasting LTP also requires the synthesis of
  new proteins and the presence of dopamine

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Synaptic Plasticity LTP and LTD

• Low-frequency stimulation of the synaptic inputs
  to a cell can decrease their strength
• Long-Term Depression (LTD) also plays a role in
  learningsome synapses are strengthened and
  others weakened
• 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.
• Like LTP, requires activation of NMDA receptors
• LTD involves a decrease in AMPA receptors

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Synaptic Plasticity LTP and LTD

• Other Forms of LTP
• Some forms of LTP do not involve NMDA receptors
  and are not blocked by AP5 (CA3).
• For example, mossy fiber input from dentate gyrus
  to CA3
• Presynaptic changes only no alterations in
  structure of dendritic spines

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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Figure 13.18 The Major Divisions of the Visual
Cortex of the Rhesus Monkey

• Primary visual cortex receives information from
  the lateral geniculate nucleus of the thalamus
• Ventral Stream pathway of information from the
  primary visual cortex to the temporal lobe, which
  is involved in object recognition (what
  pathway).
• Dorsal Stream pathway of information from the
  primary visual cortex to the parietal lobe, which
  is involved with perception of the location of
  objects (where pathway).

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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Figure 13.21 Conditioned Emotional Responses
Information about the CS US converge in the LA
so synaptic changes responsible for learning
could take place in this area Hebb rule - weak
synapses (from tone) are strengthened when US
activates neurons in the LA.LA neurons fire and
activate CN which evokes the response (Ch 11)
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Classical Conditioning

• Evidence for the involvement of lateral nucleus
  of the amygdala in CER
• Changes in the LA responsible for CER learning
  involve LTPand is accomplished through
  activation of the NMDA receptor
• LTP
• Injection of drugs that block LTP into the
  amygdala prevents the establishment of
  conditioned emotional responses
• CER training (tone-shock pairings) causes AMPA
  receptors to be driven into dendritic spines of
  synapses between LA neurons and axons that
  provide auditory input

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Classical Conditioning
Rumpel et al., (2005) used a virus to insert a
gene for a fluorescent dye coupled to a subunit
of the AMPA receptor into the LA of ratslearning
caused AMPA insertion
They also inserted a gene for a dye coupled to a
defective subunit of the AMPA receptorthe
defective subunit prevented AMPA insertion and
conditioning did not take place
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Classical Conditioning

• Infusion of many drugs into the LA that prevent
  LTP disrupt acquisition of a CER
• Conclusion
• LTP in the amygdala, mediated by NMDA receptors,
  plays a critical role in the establishment of CER

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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Instrumental Conditioning

• Instrumental conditioning involves a connection
  between a particular stimulus and a particular
  response
• 2 major pathways between sensory association
  cortex and motor association cortex
• Direct transcortical connections
• Involved in episodic memory (along with HIP)
• Connections via the basal ganglia and thalamus
• 2 pathways play different roles

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Basal Ganglia

• Learned behaviors become automatic and routine,
  they are transferred to the basal ganglia
• Leaving the transcortical circuits free to learn
  new tasks

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Figure 13.23 The Basal Ganglia and Their
Connections

• Neostriatum (caudate nucleus putamen) receives
  sensory input from all regions of the cerebral
  cortex. Also receives information from frontal
  lobes about movement (planned or in progress).
• Outputs are sent to GP which sends information
  back to frontal cortex to premotor cortex (where
  plans for movement are made) and motor cortex
  (where movement is executed)

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Instrumental Conditioning

• Basal Ganglia
• Studies of laboratory animals have indicated
  that
• lesions of the basal ganglia disrupt instrumental
  conditioning without affecting other forms of
  learning.
• Fernadez-Ruiz et al., (2001) destroyed portions
  of the caudate and putamen that receive visual
  information from the ventral stream
• Lesions did not disrupt visual perceptual
  learning
• Impaired the monkeys ability to learn to make a
  visually guided operant response
• Williams and Eskandar (2006) as monkeys learned
  a operant response, the rate of firing of single
  neurons in the caudate nucleus increased
• The activity of caudate neurons is correlated
  with rate of learning
• Blocking NMDA receptors in the basal ganglia with
  an injection of AP5 disrupts learning guided by a
  simple visual cue

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Instrumental Conditioning - Reinforcement

• Neural circuits involved in reinforcement
  discovered by Olds Milner, 1954.
• Reinforcement
• Neural Circuits Involved in Reinforcement
• Ventral Tegmental Area (VTA) group of
  dopaminergic neurons in the ventral midbrain
  whose axons form the mesolimbic and mesocortical
  systems and are important in reinforcement.
• Nucleus Accumbens nucleus of the basal
  forebrain near the septum receives dopamine from
  neurons of the VTA and is thought to be involved
  in reinforcement and attention.
• See Figure 13.24

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Figure 4.13 Dopaminergic Pathways in a Rat Brain
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Instrumental Conditioning

• Reinforcement
• Microdialysis studies have revealed that release
  of DA in the NA is caused by
• reinforcing electrical stimulation of the medial
  forebrain bundle (connects VTA to NA) or the VTA
• administration of cocaine or amphetamine
• presence of natural reinforcers such as water,
  food, sex partner
• fMRI indicates activity in NA during reinforcing
  events

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Instrumental Conditioning

• Functions of the Reinforcement System
• To detect reinforcing stimuli.
• To strengthen the connections between the neurons
  that detect the discriminative stimulus (i.e.,
  sight of lever) and the neurons that produce the
  instrumental response (i.e., lever press).

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Instrumental Conditioning

• Reinforcement occurs when neural circuits detect
  a reinforcing stimulus and cause the activation
  of dopaminergic neurons in the VTA
• A stimulus that serves as a reinforcer on one
  occasion may fail to do so on another
• Reinforcement system is not automatically
  activated when particular stimuli are present
  activation also depends on the state of the animal

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Instrumental Conditioning

• Detecting reinforcing stimuli
• Reinforcement system appears to be activated by
  unexpected reinforcing stimuli
• First DA in VTA responded rapidly when the
  reinforcing stimuli was present
• Once the animals learn the task, VTA neurons are
  activated to the learned stimuli
• If a reinforcing stimulus does not occur when
  expected, the activity of dopaminergic neurons
  decreases
• Berns et al., (2001) increased activity in NA
  (fMRI) when tasty drink was given unpredictably,
  no increase if predictable
• Activity of these neurons sends a signal that
  there is something to be learned

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Instrumental Conditioning

• Prefrontal cortex provides input to VTA
• PFC involved in devising strategies, making
  plans, evaluating progress toward a goal.
• May turn on reinforcement mechanism when it
  determines that ongoing behavior is close to goal

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Instrumental Conditioning

• Strengthening neural connections
• DA induces synaptic plasticity by facilitating
  associative LTP
• NA, amygdala, prefrontal cortex

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Chapter Overview

• The Nature of Learning
• Synaptic Plasticity Long-Term Potentiation and
  Long-Term Depression
• Perceptual Learning
• Classical Conditioning
• Instrumental Conditioning
• Relational Learning

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Relational Learning

• Includes the establishment and retrieval of
  memories of events, episodes and places

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Relational Learning

• Human Anterograde Amnesia
• Anterograde Amnesia amnesia for events that
  occur after some disturbance to the brain.
• Retrograde Amnesia amnesia for events that
  happened before some disturbance to the brain.

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Figure 13.27 A Schematic Definition of Retrograde
Amnesia and Anterograde Amnesia
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Relational Learning

• Human Anterograde Amnesia
• Korsakoffs Syndrome permanent anterograde
  amnesia caused by brain damage from chronic
  alcoholism or malnutrition.
• Medial temporal lobe damage also produces
  anterograde amnesia (i.e., H.M.)
• Based on extensive work with H.M., Milner
  colleagues concluded
• The hippocampus is not the location of LT
  memories nor is it necessary for the retrieval
  of LT memories
• The hippocampus is not the site of immediate (ST)
  memories
• The hippocampus is important for converting ST
  memories into LT memories

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Relational Learning

• Human Anterograde Amnesia
• Consolidation process by which short-term
  memories are converted to long-term memories.

Figure 13.28 A Simple Model of the Learning
Process
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Relational Learning

• Spared Learning Abilities
• Not a total failure in learning ability
• Perceptual Learning
• Visual recognition of incomplete objects (Figure
  13.29)
• Face Recognition
• Stimulus-Response Learning
• HM could learn a classically conditioned eyeblink
  response
• Instrumental conditioning task visual
  discrimination task in which pennies were given
  for correct responses
• Motor Learning
• Serial reaction time task

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Figure 13.30 The Serial Reaction Time Task
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Relational Learning

• So, even though amnesics can perform some tasks
  they have no memory of having ever learned
  themled to the notion that the brain has
  multiple memory systems
• Declarative and Nondeclarative Memories
• Declarative (explicit) Memory memory that can
  be verbally expressed.
• Nondeclarative (implicit) Memory memory whose
  formation does not depend on the hippocampal
  formation a collective term for perceptual,
  stimulus-response, and motor memory.
• Appear to be automatic, do not require deliberate
  attempts to memorize
• Acquisition of specific behaviors and skills
• Do not need to be able to describe these
  activities in order to do them

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Table 13.1

• Declarative Memory Tasks
• Remembering past experiences
• Finding ones way in new environment
• Nondeclarative Memory Tasks
• Learning to recognize broken drawings
• Learning to recognize pictures and objects
• Learning to recognize faces
• Learning to recognize melodies
• Classical conditioning
• Instrumental conditioning
• Learning sequence of button presses

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Relational Learning

• Anatomy of Anterograde Amnesia
• Damage to the hippocampus or to regions of the
  brain that supply its inputs and receive its
  outputs causes anterograde amnesia
• HIP formation CA fields, DG and SUB major
  input is from EC
• Outputs of Hip (from CA1 and SUB) also go back to
  EC, and PC and parahip cortex
• Perirhinal Cortex region of limbic cortex
  adjacent to the hippocampal formation that relays
  information between entorhinal cortex and other
  regions of the brain.
• Parahippocampal cortex region of the limbic
  cortex adjacent to the hippocampal formation that
  shares the same general role as the perirhinal
  cortex.

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Cortical Connections of the Hippocampal Formation

• Figure 13.31

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Figure 13.32 The Major Subcortical Connections of
the Hippocampal Formation

• Hip also receives subcortical input via the
  fornix
• Fornix carries dopaminergic input from VTA
• Fornix also connects the HIP with the mammillary
  bodies (located in post. Hypo.)
• MMB degenerate in Korsakoffs syndrome

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Relational Learning

• Role of the Hippocampal Formation in
  Consolidation of Declarative Memories
• HIP not really important for STM or LTM but seems
  to be important for declarative memory formation
• HIP receives input from sensory and motor cortex
  and from subcortical regions (BG and AMG), it
  then processes this information and sends
  projections back to these same regions and
  somehow modifies the memories being stored there
• Hippocampus is involved in modifying memories as
  they are being formed.
• The order in which events occurred
• Contextual information
• Relationships among elements

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Rational Learning

• Hippocampus
• Time-limited role
• Anterograde amnesia is usually accompanied by
  retrograde amnesia
• The duration of the retrograde amnesia related to
  the amount of damage to the MTL
• Damage limited to hipp retrograde amnesia
  lasting few years
• Damage to hipp entrorhinal cortex retrograde
  amnesia 1-2 decades
• Damage to MTL spared memories from early life
• Gradual process controlled by hipp transforms
  memories located elsewhere
• Before transformation is complete, hipp is
  required for retrieval of memories
• Later, retrieval of memories can occur if hipp
  has been damaged

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Relational Learning

• Declarative Memory
• Episodic and Semantic Memories
• Episodic Memory memory of a collection of
  perceptions of events organized in time and
  identified by a particular context.
• Specific to a particular time and place
• Semantic Memory memory of facts and general
  information.
• Do not include information about the context in
  which the facts were learned
• Episodic memory must be learned all at once
• Semantic Memory - can be acquired gradually
• Requires the hippocampus

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• Semantic Dementia loss of semantic memories
  caused by progressive degeneration of the
  neocortex of the lateral temporal lobes.
• Difficulty naming objects
• Difficulty understanding the meaning of words

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Relational Learning

• Spatial Memory
• Memory for spatial information used to move
  around ones environment and get from one place
  to another.
• Role of Hippocampus in Spatial Memory
• Damage to (right) HIP causes spatial memory
  impairments
• London taxi drivers have bigger HIP than control
  subjects
• longer an taxi driver had spent in this
  occupation, the larger the volume of rt hipp
• Place Cells special neurons in the hippocampus
  that are directly involved in navigation in space
  (rats).
• Virtual-reality towns
• Spatial Strategy maze learning strategy based
  on spatial cues activation of HIP (fMRI).
• Response Strategy maze learning strategy based
  on a series of responses (turns) activation of
  caudate nucleus.
• People who tend to use spatial strategies
  larger hipp
• People who tend to follow response strategies
  larger caudate

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Relational Learning

• Relational Learning in Laboratory Animals
• Spatial Perception and Learning
• Morris Water Maze

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Morris Water Maze
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Spatial Learning

• Damage to the hippocampus animals swim in what
  appears to be an aimless fashion until they
  finally encounter the platform
• Hippocampal lesions disrupt navigation in homing
  pigeons
• Hippocampus of birds and rodents that store seeds
  in hidden caches and later retrieve them is
  larger than that of animals that dont

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Relational Learning

• Relational Learning in Laboratory Animals
• Hippocampal Place Cells
• Found in dorsal hippocampus in rats (corresponds
  to the posterior hippocampus in humans)
• fire at a high rate when the animal is in a
  particular location, called the cells place
  field
• fire at a low rate when the animal is in a
  different location
• First discovered by OKeefe Dostrovsky

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OKeefe Dostrovsky (1971)
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Relational Learning

• Relational Learning in Laboratory Animals
• Role of Hippocampal Formation in Memory
  Consolidation
• Time limited role in memory
• Mice trained in water maze inactivate HIP with
  lidocaine 1 day later or 30 days later (Figure
  13.40)
• Memory Reconsolidation
• A process of consolidation of a memory that
  occurs subsequent to the original consolidation
  that can be triggered by a reminder of the
  original stimulus.

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Phases of MemoryReconsolidation
Acquisition - the pairing of the context/cue to
the aversive stimuli
Train
Reactivate
Test
Evidence suggests that reactivation of a memory
can return it to a labile state requiring
reconsolidation via protein synthesis
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Figure 13.41 A Schematic Description of the
Experiment by Misanin, Miller, and Lewis (1968)
84
Reconsolidation of Memories

• Reconsolidation requires LTP
• Injection of anisomycin (blocks protein synthesis
  and prevents memory consolidation), blocks
  reconsolidation

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Relational Learning

• Relational Learning in Laboratory Animals
• Role of LTP in memory
• When rats learn mazes, strength of population
  EPSP in CA3 increases
• Mutations targeted at NMDA receptors in CA1
• Prevented establishment of LTP
• Poor spatial learning on Morris water maze
• Hippocampal Neurogenesis
• New neurons can be produced in the hippocampus of
  the adult brain (DG)
• Training on relational tasks increases
  neurogenesis
• Easier to establish LTP with these new neurons