Chapter 11 Learning, Memory, and Amnesia

Learning

The brain's ability to change in response to experience.

Memory

The brain's ability to store and access the learned effects of experiences.

Amnesia

Any pathological loss of memory.

Bilateral medial temporal lobectomy

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

Hippocampus

A structure of the medial temporal lobes that plays a role in various forms of memory.

Amygdala

A structure in the anterior temporal lobe, just anterior to the hippocampus; plays a role in emotion.

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

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

Anterograde amnesia

Loss of memory for events occurring after the amnesia-inducing brain injury.

Short-term memory

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

Long-term memory

Memory for experiences that endures after the experiences are no longer the focus of attention.

Digit span

The longest sequence of random digits that can be repeated correctly 50 percent of the time – most people have a digit span of 7.

Global amnesia

Amnesia for information presented in all sensory modalities.

Incomplete-pictures test

A test of memory measuring the improved ability to identify fragmented figures that have been previously observed.

Remote memory

Memory for experiences in the distant past.

Memory consolidation

The transfer of short-term memories to long-term storage.

Explicit memories

Conscious memories.

Implicit memories

Memories that are expressed by improved performance without conscious recall or recognition.

Medial temporal lobe amnesia

Amnesia associated with bilateral damage to the medial temporal lobes; its major features are anterograde and retrograde amnesia for explicit memories, with preserved intellectual functioning.

Repetition priming tests

Tests of implicit memory; in one example, a list of words is presented, then fragments of the original words are presented and the subject is asked to complete them.

Semantic memories

Explicit memories for general facts or knowledge.

Episodic memories

Explicit memories for the particular events and experiences of one's life.

Global cerebral ischemia

An interruption of blood supply to the entire brain.

Pyramidal cell layer

One of the major layers of cell bodies in the hippocampus.

CA1 subfield

A region of the hippocampus that is commonly damaged by cerebral ischemia.

Transient global amnesia

A sudden onset severe anterograde amnesia and moderate retrograde amnesia for explicit episodic memory that is transient – typically lasting only between 4 to 6 hours.

Korsakoff's syndrome

A neuropsychological disorder that is common in alcoholics and whose primary symptoms include memory loss, sensory and motor dysfunction, and, in its advanced stages, severe dementia.

Mediodorsal nuclei

A pair of thalamic nuclei, damage to which is thought to be responsible for many of the memory deficits associated with Korsakoff's syndrome.

Medial diencephalic amnesia

Amnesia that is associated with damage to the medial diencephalon (e.g., Korsakoff's amnesia).

Alzheimer's disease

The most common form of dementia in the elderly. Its three defining characteristics are:neurofibrillary tangles, amyloid plaques, and neuron loss.

Basal forebrain

A midline area of the forebrain, which is located just in front of and above the hypothalamus and is the brain's main source of acetylcholine.

Posttraumatic amnesia (PTA)

Amnesia produced by a nonpenetrating head injury (a blow to the head that does not penetrate the skull).

Electroconvulsive shock (ECS)

An intense, brief, diffuse, seizure-inducing current administered to the brain via large electrodes attached to the scalp.

Standard consolidation theory

The theory that memories are temporarily stored in the hippocampus until they can be transferred to a more stable cortical storage system. Also known as dual-trace theory.

Dual-trace theory

The theory that memories are temporarily stored in the hippocampus until they can be transferred to a more stable cortical storage system. Also known as the standard consolidation theory.

Engram

A change in the brain that stores a memory.

Reconsolidation

The theory that each time a memory is retrieved from long-term storage, it is temporarily held in a labile (changeable or unstable) state in short-term memory, where it is susceptible to posttraumatic amnesia. This susceptibility remains until it is consolidated again.

Delayed nonmatching-to-sample test

A test in which the subject is presented with an unfamiliar sample object and then, after a delay, is presented with a choice between the sample object and an unfamiliar object, where the correct choice is the unfamiliar object.

Medial temporal cortex

Cortex in the medial temporal lobe that lies adjacent to the hippocampus and amygdala.

Mumby box

An apparatus that is used in the rat version of the delayed nonmatching-to-sample test.

Morris water maze test

A widely used test of spatial memory in which rats must learn to swim directly to a platform hidden just beneath the surface of a circular pool of murky water.

Radial arm maze test

A widely used test of rats' spatial ability in which the same arms are baited on each trial, and the rats must learn to visit only the baited arms once per trial.

Reference memory

Memory for the general principles and skills that are required to perform a task.

Working memory

Temporary memory that is necessary for the successful performance of a task on which one is currently working.

Place cells

Neurons that respond only when the subject is in specific locations (i.e., in the place fields of the neurons).

Entorhinal cortex

An area of the medial temporal cortex that is a major source of neural signals to the hippocampus.

Grid cells

Entorhinal neurons that each have an extensive array of evenly spaced place fields, producing a pattern reminiscent of graph paper.

Jennifer Aniston neurons

Neurons, such as those found in the medial temporal lobe, that respond to ideas or concepts rather than to particulars. Also known as concept cells.

Concept cells

Cells, such as those found in the medial temporal lobe, that respond to ideas or concepts rather than to particulars. Also known as Jennifer Aniston neurons.

Engram cells

Neurons that maintain an engram.

Inferotemporal cortex

The cortex of the inferior temporal lobe, in which is located an area of secondary visual cortex.

Prefrontal cortex

The areas of frontal cortex that are anterior to the frontal motor areas.

Cerebellum

A metencephalic structure that is thought to participate in the storage of memories of learned sensorimotor skills.

Striatum

A structure of the basal ganglia that is the terminal of the dopaminergic nigrostriatal pathway.

Long-term potentiation (LTP)

The enduring facilitation of synaptic transmission that occurs following activation of synapses by high-intensity, high-frequency stimulation of presynaptic neurons.

NMDA receptors

Glutamate receptors that play key roles in the development of stroke-induced brain damage and long-term potentiation at glutaminergic synapses.

Glutamate

The most prevalent excitatory neurotransmitter in the CNS.

Dendritic spines

Tiny protrusions of various shapes that are located on the surfaces of many dendrites.

Transcription factors

Intracellular proteins that bind to DNA and influence the operation of particular genes.

Long-term depression (LTD)

A long-lasting decrease in synaptic efficacy (the flip side of LTP) that occurs in response to prolonged low-frequency stimulation of presynaptic neurons.

Metaplasticity

The modulation of long term potentiation (LTP) and / or long-term depression (LTD) induction by prior synaptic activity.

Infantile amnesia

The normal inability to recall events from early childhood.

Nootropics (smart drugs)

Drugs that purportedly improve memory.