Learning & Memory

Chapter 12

Learning

Learning the process by which experiences change

the nervous system resulting in changes in behavior

MemoriesChanges in the nervous system and

behaviorNetworksSynaptic plasticity

Learning

Perceptual learning

Stimulus-response learning

Motor learning

Relational learning

Hebbian Learning

Hebb ruleLearning involves

the strengthening of a synapse that is repeatedly active when the post synaptic neuron fires

Classical vs. Operant Conditioning

Classical Conditioning

Unconditioned Stimuli (US)

Unconditioned Response (UR)

Neutral Stimuli (NS)

Conditioned Stimuli (CS)

Conditioned Response (CR)

Operant Conditioning

Target behavior

ConsequenceThe stimuli

Effect on behaviorReinforcePunish

Classical vs. Operant Conditioning

Long-term Potentiation

Long-term potentiation (LTP)A long-term increase in the excitability of a

neuron to a particular synaptic input caused by repeated high frequency activity of that input.

Sensitization

Long-term PotentiationHippocampal formation

Synaptic strengthening occurs when synapses are active while the membrane of the postsynaptic cell is depolarized

Long-term PotentiationAssociative LTPconcurrent

stimulation of weak and strong synapses to a given neuron

strengthens the weak synapses

Receptors

NMDA Receptor

glutamate receptor that controls a calcium channel that is normally blocked by Mg2+ ionsneurotransmitter-

and voltage-dependent ion channel

AMPA Receptor

An ionotropic glutamate receptor that controls a sodium channel; when open, it produces EPSPs.

Long-term Depression

Long-term depression (LTD)

A long-term decrease in the excitability of a neuron to a particular synaptic input

Caused by stimulation of the terminal button while the postsynaptic membrane is hyperpolarized or only slightly depolarized.

Classical Conditioning

Conditioned emotional responses

AmygdalaLateral nucleus

Classical Conditioning

Cerebellum

Lateral interpositus (LIP) nucleus

Timing of brief intervals

>1 second

Instrumental Learning(a.k.a. operant conditioning)

Basal GangliaAlso important

for implicit procedural memories

Instrumental Learning: Reward

Nucleus accumbensReceives inputs from VTA

Ventral tagmental areaDopminergic

Involves memory for current thoughts

DurationRoughly 20 seconds without rehearsalCan be increased by maintenance

rehearsal

Capacity5-9 itemsCan by increased by chunking

Short-Term/Working Memory

Long-Term Memory (LTM)

Relatively permanent memory storage

Believed to have unlimited capacity

Several systems of organization

Episodic vs. Semantic

Non-declarative vs. Declarative

Semantic and Episodic Memory

Semantic memoryFactsWordsGeneral knowledge

Episodic memoryExperiencespersonal events

Procedural vs. Declarative Memory

Procedural memory: Knowing “how”HabitsMotor skillsBasal Ganglia

Declarative memory: Knowing “that”Includes semantic and episodic memory

Declarative vs. Non-declarative Memory

Declarative memoryConscious, EffortfulIncludes semantic and episodic memories

Non-declarative memoryAutomatic, HabitualIncludes perceptual, motor, stimulus-

response memoriesDoes not require hippocampal formation

Amnesia

Typical Presentation of Amnesia

Normal working memory

Severe anterograde amnesia for declarative memoryespecially episodic memories.

Some degree of retrograde amnesiamainly limited to episodic memories.

Better implicit than explicit memory.

Nearly intact procedural memory.

The hippocampal formation

Consolidation of memories

Declarative memories

Spatial Memory

Contextual Memorydetail

Neurogenesis

New neurons more amenable to synaptic plasticity

Relational learning

Korsakoff’s Syndrome

Wernicky-Korsakoff syndrome

Sever thiamine deficiencyB1

Symptoms similar to prefrontal cortex damage apathy, confusion, and memory loss.

hippocampal damage impairment of episodic memory and sparing of implicit

memory.

Confabulations

Alzheimer’s Disease

Plaques & Tangles

Cell Death