PSY 335

Memory and Amnesia

Memory Disorders

Midterm Results

Score Grade N

51-60 A 4

45-50 B 13

39-44 C 13

33-38 D 7

0-32 F 3

Top score = 59,

Top score for curve-setting = 57

Influences on Memory

Alcohol – Bits & Pieces

Stress -- Kolb & Whishaw Seg 32 (CD 2)

Diabetes – Kolb & Whishaw Ch 13 Seg 6

(CD 3)

Kinds of Memory Disorders

Organic – having a physical cause

Functional – having a psychological

cause

Dys (as a prefix) means difficulty or

limited ability to perform.

A (as a prefix) means complete inability

or lack of a function.

Alcohol & Memory

Alcoholic amnesia – alcohol prevents

consolidation so nothing is remembered and

no memory can be recovered.

Alcoholic blackout – state-dependent memory,

so recall is possible if one is back in the same

state.

Because many crimes are committed while

drunk, memory failure is frequently blamed on

alcohol.

Sleep & Memory

New sleep studies suggest a "memory life-cycle” with three stages - stabilization, consolidation, and re-consolidation. • Initial stabilization takes up to 6 hours.

• Sleep needed for consolidation, deep non-REM

• Alcohol disrupts consolidation

Sleep deprivation produces effects similar to aging. • Procedural memory and recognition memory are most

strongly affected.

Sources of Organic Dysfunction

Accident • Car accidents and other injuries (e.g., N.A.)

• War

Disease • Encephalitis (viral) – inflammation of the lining

of the brain, causing swelling.

• Stroke

• Alzheimer’s disease

• Korsakov’s syndrome (prolonged alcoholism)

Alzheimer’s Disease

A fatal degenerative disease caused by

cell failure – neurofibrillary tangles and

plaques that interfere with cell function.

• All areas of the brain are eventually affected,

but frontal lobes and memory go first.

Confusions and memory problems do

not resemble normal aging, amnesia or

other memory problems.

http://upload.wikimedia.org/wikipedia/commons/a/a7/Alzheimer_dementia_%283%29_presenile_onset.jpg

Classification of Disorders

See Parkin, Ch 5, for tests used to assess memory problems.

Disorders classified by type of symptom: • Generalizing – confusion, fuzziness, mental

slowing.

• Localizing – few generalizing symptoms but impairment of specific functions.

Clusters of symptoms are a syndrome. • Concern about symptoms is a symptom itself.

Frontal Lobe Deficits

Confabulation – production of a false memory. • Momentary confabulation – responses that

could be correct.

• Fantastic confabulation – responses clearly fictional.

Source amnesia – fact is remembered but not the source.

Memory of temporal order.

Frontal Lobe Deficits (Cont.)

Impaired recall – more “ugly stepsisters,”

no categorization.

Metamemory is impaired, including FOK

judgments and monitoring of search.

False recognization:

• Increased false alarms

• Increased intrusions

Frontal Lobe Deficits (Cont.)

Faulty encoding and poor representation

may be a cause of poorly focused

search.

• Information is needed to guide search.

The left frontal lobe guides encoding.

The right frontal lobe guides retrieval.

Frontal Lobe Deficits (Cont.)

Emotional deficits: • Cognitive apathy, lack of motivation

• Flattened affect

Impaired awareness of memory loss: • Inaccurate assessment of performance

• Lack of distress

If confabulations are believed by others, no feedback on normalcy.

Alien Hand (Anarchic Hand)

Syndrome – a Frontal Lobe Deficit

Peter Sellars in

“Dr. Strangelove:

or How I learned to

story worrying and

love the bomb”

Damage to the Parietal

Association Cortex

Confusion about directions, inability to use

words describing spatial relations:

• Under, up, down

Inability to name body parts or point to parts of

the body.

Capgras syndrome (rt. Posterior parietal)

inability to recognize close family members

• Sometimes animals or even furniture

• Invasion of the body snatchers

Reading & Writing Disorders

Alexia – inability to read

Agraphia – inability to write

Caused by damage to the left angular

gyrus which integrates information from

the sensory modalities.

Pure Word Deafness

A person can hear and speak, read and write normally but cannot understand speech.

Occurs with bilateral destruction of the auditory cortex or disconnection from Wernicke’s area.

Because Wernicke’s area is not damaged, speech produced is OK.

Perceptual Deficits

Aphasia – involves inability to name

something.

Agnosia – involves inability to recognize

something.

Visual agnosias – inability to combine

individual visual impressions into

complete patterns.

Types of Visual Agnosias

Object agnosia – inability to recognize common objects.

Prosopagnosia – inability to recognize faces.

Color agnosias: • Achromatopsia (cortical color blindness)

• Color anomia – inability to name colors.

• Color agnosia – inability to recognize colors

Other Agnosias

Amusia – tone deafness, melody deafness, disorders of rhythm, measure, tempo.

Astereoagnosia – inability to recognize the nature of an object by touch.

Asomatoagnosia – knowledge of one’s own body. • Indifference to illness, asymbolia for pain

Pure Anomia

Loss of memory of words (anomic aphasia) • Cannot name pictures of common objects

• Difficulty reading and writing

Produced by damage to either Broca’s or Wernicke’s area (fluent anomia).

Use circumlocutions to get around missing words.

Broca’s Aphasia

Broca’s area may contain memories of the

movements needed to produce speech.

Produces three deficits:

• Anomia – word-finding difficulty

• Agrammatism – loss of grammatical construction

• Difficulty with articulation

Slow, laborious, nonfluent speech without

function words with with content words.

Conduction Aphasia

Disruption of verbal short term memory

due to damage to the subcortical axons

that connect Broca & Wernicke’s areas.

Results in poor repetition – only

meaningful words can be repeated

(through other means).

• Non-words cannot be repeated (blaynge).

Amnesic Syndrome

Short term memory is intact (unimpaired)

Anterograde amnesia present affecting both recognition and recall tasks.

Retrograde amnesia present, but extent varies.

Semantic memory largely intact but can be affected by antero & retro amnesias.

Procedural memory is intact.

Causes of Amnesic Syndrome

Damage to: • Hippocampus

• Temporal cortex

• Diencephalon (especially mamillary bodies)

Herpes simplex encephalitis

Korsakoff’s syndrome (thiamine deficiency plus chronic alcoholism)

Direct injury (H.M., N.A.)

Anterograde Amnesia

No new declarative information can be added to long-term memory

Events from the present are quickly forgotten

Usually accompanied by retrograde amnesia.

Performance on IQ tests is unimpaired because it relies on info learned in past.

Retrograde Amnesia

Declarative information from the past is

forgotten.

Information is forgotten in a temporal gradient

(based on time):

• Ribot’s law – newer information forgotten first.

• Both semantic and episodic information show this

gradient.

Difficult to test due to differences in life

experiences, impairment varies.

Focal Retrograde Amnesia

Loss of remote memory unaccompanied

by anterograde amnesia.

May occur when the temporal cortex is

damaged but not the hippocampus.

Cases reported without head injury and

with loss of procedural memory are

probably malingering (faking).

Evidence for Implicit Memory

Alzheimer’s patients show impaired

priming.

Huntington’s Chorea patients show

normal priming but impaired procedural

memory.

Procedural memory and priming are

spared by amnesia.