Memory Systems - Mind, Brain and Behaviour - Lecture Slides, Slides of Human ethology

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Memory SystemsMemory

Systems

What is Memory?

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emory is a change in the synapses of the neurons comprising a network.M

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emories are not static “records” but products of a change in the connectionsamong nerve cellsamong nerve cells. †

Memories extract and store the meanings ofevents not their exact detailsevents, not their exact details.

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Sensory aspects are reexperienced not recalled. „

Recall is reconstructed not just retrieved „

Recall is reconstructed, not just retrieved.

Where is Memory?

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oth cortical and subcortical structures are involved in creating memories.Al h

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though memories appear to be stored in the cortex, they are:

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stributed – spread out in a network

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Redundant – represented in multiple ways H bbi

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ebbian cell assemblies (loops) permit access at various points in a network.

Stages of Memory

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ensory buffers – one for each sense: „^

Iconic – for visual informationE h i

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choic – for auditory information

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Working memory/short term memory:

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Limited capacity – 7 plus or minus 2 „

Capacity can be expanded by chunkingE

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xecutive functions

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Long term memory – permanent.

Working Memory †

Unimpaired in amnesics. †

In humans, localized to frontal lobes. †

Delayed development of frontal lobes inhumans and monkeys:humans and monkeys:

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“A not B” task „

Can’t tolerate delays (8-10 sec) until „

Can t tolerate delays (8 10 sec) until1-1/2 yrs old

Infantile Amnesia †

Inability to remember events of one’schildhood before ages 3-4.

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10 year olds couldn’t remember preschoolclassmates „

Attributed to immaturity of memory systems inchildren.

Procedural vs Declarative

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rocedural memory – memory for how to do things, skills.D

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eclarative memory – memory for abstract knowledge, facts and events of one’s life.O l

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nly memory for events of one’s life is affected by amnesia – not procedural memoryor memory for factsor memory for facts.

Explicit vs Implicit †

Implicit memory – does not involve consciousawareness – unimpaired in amnesics.

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rocedural memory

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Priming, recognition tasks „

Classical conditioning habituation „

Classical conditioning, habituation „

Semantic memory

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Explicit memory – involves conscious attention – †

Explicit memory

involves conscious attention

impaired in amnesics.^ „

Episodic and autobiographical memory, recall

Types of Amnesia †

Damage to Temporal Lobe – H.M. †

Damage to Thalamic Structures – N.A.

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Most impaired with verbal material.

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Korsakoff’s Syndrome †

Korsakoff s Syndrome

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Chronic alcoholics with thiamine deficiency „

Retrograde and anterograde amnesia „

Retrograde and anterograde amnesia.

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Electroconvulsive Shock Therapy (ECT)

Amnesia and Forgetting †

Forget at normal rate – thalamic (diencephalon):

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orsakoff’s patients

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Monkeys with medial thalamic lesions

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Forget rapidly

hippocampus:

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Forget rapidly – hippocampus:

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H.M. „

Bilateral ECT „

Bilateral ECT „

Monkeys with amygdala/hippocampus lesions

Cellular Mechanisms †

Habituation involved suppression of actionpotentials through decreased release ofneurotransmitter – change is at the synapse. „

Sensitization – increased neurotransmitter release

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Explicit memory involves long-termpotentiation, LTP (a physical change top

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neurons) in hippocampus and neocortex. „

See Chapter 24 for details

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