Bipsych: Mica, Marilou, Nyang

NEUROPLASTIC PROCESSES

The ability of the brain to change its functioning in response to experience.

LEARNING

How experience changes the brain.

MEMORY

How these changes are stored and subsequently reactivated.

BILATERAL MEDIAL TEMPORAL LOBECTOMY

The removal of the medial portions of both temporal lobes, including most of the hippocampus, the amygdala, and adjacent cortex.

LOBECTOMY

An operation in which a lobe, or a major part of one, is removed from the brain.

LOBOTOMY

An operation in which a lobe, or a major part of one, is separated from the rest of the brain by a large cut but is not removed.

RETROGRADE AMNESIA

(Backward-acting) Loss of memory for events or information learned before the amnesia-inducing brain injury.

ANTEROGRADE AMNESIA

(Forward-acting) Loss of memory for events occurring after the amnesia-inducing brain injury.

SHORT-TERM MEMORY

Storage of new information for brief periods of time while a person attends to it.

LONG-TERM MEMORY

Storage of new information once the person stops attending to it.

DIGIT SPAN + 1 TEST

A classic test of verbal long-term memory where H.M. was asked to repeat 5 digits at 1-second intervals, with another digit added each time. H.M. couldn't repeat an 8-digit sequence, while normal subjects can correctly repeat about 15 digits after 25 trials.

BLOCK-TAPPING MEMORY-SPAN TEST

A test for global amnesia (amnesia for information presented in all sensory modalities). H.M. had a span of 5 blocks (normal range) but could not learn a sequence of 6 blocks even after 12 repetitions.

MIRROR-DRAWING TEST

A task where a person must draw within the boundaries of a star-shaped target while watching their hand in a mirror. H.M. improved over three days, indicating retention, but had no memory of having done it before.

INCOMPLETE-PICTURES TEST

A nonsensorimotor test of memory that employs five sets of fragmented drawings. H.M. showed improvement over 1 hour.

PAVLOVIAN CONDITIONING

A tone was sounded just before a puff of air was administered to H.M.'s eyes. Over time, the tone alone elicited an eye blink. H.M. retained the conditioned response for two years.

THREE MAJOR SCIENTIFIC CONTRIBUTIONS OF H.M.'S CASE

Medial temporal lobes play an important role in memory. Supported the theory that short-term, long-term, and remote memory have different storage modes.

REMOTE MEMORY

Memory for experiences in the distant past.

MEMORY CONSOLIDATION

The process of translating short-term memories into long-term memories.

EXPLICIT MEMORIES

Conscious LTM.

IMPLICIT MEMORIES

Unconscious LTM; demonstrated by improved test performance without conscious awareness.

MEDIAL TEMPORAL LOBE AMNESIA

Difficulty in forming explicit LTM but not implicit LTM, particularly affecting episodic memories.

REPETITION PRIMING TESTS

Tests assessing implicit memory by showing participants a list of words and later presenting fragments of those words to be completed.

WHY 2 PARALLEL MEMORY SYSTEMS?

The evolution of explicit memory systems allows for flexible use of information.

EXPLICIT LONG-TERM MEMORIES

Two varieties

SEMANTIC MEMORIES

Explicit memories for general facts or information.

EPISODIC MEMORIES

Explicit memories for personal life events (also called autobiographical memory).

AMNESIA OF KORSAKOFF'S SYNDROME

Memory disorder common in heavy alcohol consumers, largely due to thiamine deficiency. Symptoms include sensory/motor issues, extreme confusion, personality changes, and risks of liver, gastrointestinal, or heart disorders.

AMNESIA OF ALZHEIMER'S DISEASE

Progressive memory deterioration, leading to dementia and eventually terminal illness. Early signs include deficits in short-term and implicit memory. Associated with reduced acetylcholine levels due to basal forebrain degeneration.

CONCUSSION

A temporary disturbance of consciousness caused by a non-penetrating head injury.

POSTTRAUMATIC AMNESIA (PTA)

Memory loss occurring after a non-penetrating blow to the head, such as a concussion.

COMA

A pathological state of unconsciousness.

PERIOD OF CONFUSION

Characterized by disorientation and an inability to form new memories (anterograde amnesia).

MEMORY IMPAIRMENTS

Retrograde Amnesia

Anterograde Amnesia

Permanent memory loss for events during the confusion period.

ISLAND OF MEMORY

Surviving memories for isolated events during periods where other memories have been wiped out.

GRADIENTS OF RETROGRADE AMNESIA AND MEMORY CONSOLIDATION

Evidence that retrograde amnesia gradients suggest memory consolidation is a long-term process.

HEBB'S THEORY OF MEMORY CONSOLIDATION

Memories are stored in the short term by neural activity reverberating in closed circuits. ("Neurons that fire together, wire together.")

ELECTROCONVULSIVE SHOCK (ECS)

A seizure-inducing current administered to the brain to estimate how long memory consolidation takes. Studies suggest consolidation takes 10 minutes to 1 hour.

STANDARD CONSOLIDATION THEORY

The hippocampus temporarily stores memories before transferring them to more stable cortical storage.

MULTIPLE-TRACE THEORY

The hippocampus stores memories indefinitely, with repeated recall strengthening memory traces.

RECONSOLIDATION

Each time a memory is retrieved, it becomes temporarily unstable and must be reconsolidated back into long-term memory.

Monkey Version

Damage to the rhinal cortex demonstrated that medial temporal lobe amnesia is not solely due to hippocampal damage.

Rat Version

Rats with hippocampal lesions struggled with spatial memory tasks, confirming the hippocampus's role in spatial memory.

MORRIS WATER MAZE TEST

Rats with hippocampal lesions struggle to find a hidden platform in a pool, indicating spatial memory deficits.

RADIAL ARM MAZE TEST

Rats with hippocampal damage fail to avoid revisiting baited arms, showing deficits in reference and working memory.

REFERENCE MEMORY

Memory for general principles and skills needed to perform a task.

WORKING MEMORY

Temporary memory necessary for completing a current task.

WHERE ARE MEMORIES STORED?

Memories are stored diffusely throughout the brain, with different structures involved in different types of memories.

INTEROTEMPORAL CORTEX

Involved in visual memory and pattern recognition.

AMYGDALA

Strengthens emotionally significant memories.

PREFRONTAL CORTEX

Plays diverse roles in memory, though damage does not always cause amnesia.

CEREBELLUM

Stores motor memory and sensorimotor skills.

STRIATUM

Involved in habit formation and procedural memory.

LONG-TERM POTENTIATION (LTP)

The strengthening of synaptic transmission following repeated activation.

Induction

Learning phase.

Maintenance

Storage phase.

Expression

Recall phase.

LONG-TERM DEPRESSION (LTD)

The weakening of synaptic strength following prolonged low-frequency stimulation.

INFANTILE AMNESIA

The inability to recall early childhood experiences, though implicit memories may remain.

SMART DRUGS (NOOTROPICS)

Substances believed to enhance memory and cognitive function.

POSTTRAUMATIC AMNESIA & EPISODIC MEMORY

Temporary memory loss and impairment of personal experiences, places, events, and emotions.