12 Memory Systems

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12 Memory Systems

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Introduction

I. Learning and remembering distinguishes naïve from mature brain

II. Relationship between visual development and learning

A. Similar mechanisms in different cortical areas

III. Memories range from stated facts to ingrained motor patterns

IV. Anatomy: Several memory systemsA. Evident from brain lesions

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Learning & Memory

LearningAcquisition of new information

MemoryRetention of learned information

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Types of Memory

I. Long-Term, Short-Term, and Working Memory

Working memory: Active, Temporary information storage

Sensory information

Long-termmemory

Short-term memory

Consolidation

Sensory information

Long-termmemory

Short-term memory

Consolidation

Time

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Types of Memory: Long-Term

Declarative memory (explicit)Facts and events

Nondeclarative memory (implicit)Procedural memory- skills, habits, behaviors

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Types of Memory and AmnesiaAmnesia: Serious loss of memory and ability to learn

Causes: Concussion, chronic alcoholism, encephalitis, hypoxia, brain tumor, or stroke

A. Limited amnesiaB. Dissociated amnesia: Amnesia, no other

cognitive deficit (rare)C. Anterograde with Temporally-Graded Retrograde

AmnesiaD. Transient global amnesia:Caused by ischemic

episode. Short durationSymptoms: Disoriented, ask same questions repeatedly; Attacks subside in couple of hours; Permanent memory gap

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Types of Memory and Amnesia

Memory loss related to timeA. Retrograde amnesia

Forget things you already knew B. Anterograde amnesia

Inability to form new memories

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Memory Storage

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Memory Storage

I. Hebb and the Cell AssemblyA. External events are represented by cortical

cellsB. Cells reciprocally interconnected

reverberationC. Active neurons—cell assembly

1. Consolidation by “growth process”2. “Fire together, wire together”

D. Hebb and the engram1. Widely distributed among linked cells in

the assembly2. Could involve neurons involved in

sensation and perception

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Memory Storage

Hebb’s Cell Assembly and Memory Storage

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Memory Storage

Localization of Declarative Memories in the Neocortex

A. Experiments—macaque monkeys1. Differentiate objects

based on shapesB. Lesion made in area IT

1. Cannot discriminate2. Does not remember

stimulusC. Studies in humans

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Memory Storage

Electrical Stimulation of the Human Temporal Lobes

A. Penfield’s experiments1. Electrical stimulation of the temporal

lobe Complex sensationsB. Penfield’s patients: Sensations like

hallucinations, recall past experiencesC. Temporal lobe: Role in memory storageD. Temporal lobe stimulation

1. Different from stimulation of other areas of neocortex

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The Temporal Lobes and Declarative Memory Temporal

Lobectomy

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The Temporal Lobes and Declarative Memory

The Medial Temporal Lobes and Memory Processing

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The Temporal Lobes and Declarative Memory

The Medial Temporal Lobes and Memory Processing

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The Temporal Lobes and Declarative Memory

DNMS: Delayed non-match to sample

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The Temporal Lobes and Declarative Memory

DNMS: Delayed non-match to sample

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The Temporal Lobes and Declarative Memory

The Diencephalon & Memory Processing

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The Temporal Lobes and Declarative Memory

The Diencephalon: Korsakoff’s Syndrome1. Symptoms: Confusion, confabulations,

severe memory impairment, and apathyA. Alcoholics: Develop thiamin deficiency

1. Leads to symptoms: Abnormal eye movements, loss of coordination, tremors

B. Treatment: Supplemental thiamin 1. Thiamin deficiency: Structural brain

damage

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The Temporal Lobes and Declarative Memory

Role of the medial temporal lobes

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The Temporal Lobes and Declarative Memory

Morris water maze

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The Temporal Lobes and Declarative Memory

Relational memory:Spatial Navigation

Extra-Maze Cues

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The Temporal Lobes and Declarative Memory

Relational memory:Spatial Navigation

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The Temporal Lobes and Declarative Memory

Relational memory:

Transverse PatterningA>B B>C C>A

Transitive InferenceA>B B>C C>D D>E B?D

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The Striatum & Procedural Memory

I. Two elements of basal ganglia StriatumA. Caudate nucleus B. Putamen

II. Rodent Recordings and Lesions in the Striatum

A. Lesions to striatum: Disrupts procedural memory

B. Damaged hippocampal system: Degraded performance on standard maze task

C. Lesion in striatum: Impaired performance of the light task; Double dissociation

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The Striatum & Procedural Memory

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Working Memory

The Prefrontal Cortex and Working Memory Function of prefrontal cortex: self-awareness,

capacity for planning and problem solving

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Working Memory

Imaging Working Memory in the Human Brain

Numerous areas in prefrontal cortex are involved in working memory

Face Only

Face & Spatial

Spatial Only

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Working MemoryWorking Memory Updating Perseveration

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The Working Memory

Lateral Intraparietal Cortex (Area LIP) and Working Memory : Guiding eye movements

Delayed-saccade task

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Concluding Remarks

I. Learning and memoryA. Occur throughout the brain

II. MemoriesA. Duration, kind of information stored, and brain

structures involved B. Distinct types of memoryC. Different types of amnesia

1. Multiple brain systems for memory storage III. Engrams in temporal lobe neocortex

A. Physiological basis?B. Long-term memories: structural basis?

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End of Presentation