Lecture 21: Learning and Memory

Declarative Memory

Memory available to consciousness

(Ex. Daily episodes, words and their meanings, and history)

Nondeclarative Memory

Memory generally not available to consciousness

(Motor skills, associations, priming cues, and puzzle solving skills)

Phylogenetic memory

The type of memory that have developed through natural selection

Immediate memory

Fractions of a second/seconds memory

Short term memory

Seconds/minutes memory

Long-term memory

Days/years memory

B (Holding and mentally manipulating information for seconds to minutes)

Which of the following illustrates working memory?

A. Holding information in mind for less than a second

B. Holding and mentally manipulating information for seconds to minutes

C. Holding information for several days

D. Using engrams to retain information

E. Learning new motor skills

Memory consolidation

Transfer of immediate/ short-term memory into long-term memory

(Ex. Non-declarative (implicit) memory → Priming)

Digit Span

The normal human capacity for remembering relatively meaningless information is surprisingly limited → String of 7 to 9 numbers

Can be increased with practice

Associations

The role of previous knowledge and/or motivation to assist in memory

Chunking

Grouping of responses into meaningful subsets (or made-up associations)

Is facilitated by expertise (Ex. chess configurations)

Motivated memory

Hungry subjects scored better on a test of recognition memory (“have you seen this picture before?”) when they had to identify food-related items

Episodic Memory

Ex. Remembering your first day of school

A type of declarative memory

Semantic Memory

Ex. Knowing the capital of France

A type of declarative memory

Skill Learning

Ex. Knowing how to ride a bicycle

A type of nondeclarative memory

Priming

Ex. Being more likely to use a word you heard recently

A type of nondeclarative memory

Conditioning

Ex. Salivating when you see a favorite food

A type of nondeclarative memory

Anterograde Amnesia

The inability to form new memories

Retrograde Amnesia

The loss of old memories

Patient H.M.

Underwent bilateral temporal surgery → Anterograde amnesia

→ Have complete deficits in acquiring new declarative memory (Episodic and semantic)

→ Old declarative memory (before the surgery) remained intact

Non-declarative (implicit) memory remained largely intact

→ Improved / learned performance on a motor task, even though he never remembered that he had performed the task before

Ablations involved hippocampus, parahippocampal gyrus, and amygdala.

Hippocampus

Involved in declarative memory

Morris water maze → spatial learning

Patient K.C.

Lesions to the hippocampus

Severe anterograde and retrograde deficits for episodic memory

→ Suggests that the hippocampus is specific for episodic memory

Semantic memory largely intact + can acquire some new semantic memory

Consolidation of memory

Widespread projections from association neocortex converge on the hippocampal region

The output of the hippocampus is ultimately directed back to these same neocortical areas

Classical Conditioning

Pavlov and his dogs → salivating to a whistle

Unconditioned stimulus, unconditioned response → neutral stimulus, no conditioned response → neutral stimulus + unconditioned stimulus, unconditioned response → conditioned stimulus → conditioned response

Operant Conditioning

Form of learning in which an individual's behavior is modified by its consequences

→ Skinner and his rats

Reinforcement, punishment, and extinction

Reinforcement

A consequence that causes behavior to occur more often

Punishment

A consequence that causes a behavior to occur less frequently

Extinction

Caused by the lack of any consequence following a behavior

basal ganglia

Parkinson’s disease reveals a role for this in nondeclarative memory

Aging and Attention

Decrease in brain volume mostly related to loss of synapses/connections, pines), rather than loss of neurons

Impairment of executive functions as a key contributor to age-related declines

→ Attention → slowing down of information processing

→ Short term/working memory → declines early

Alzheimer’s disease

Amyloid plaques → Mutant genes (presenilin 1 and 2) increase risk to develop toxic form of Aβ

Neurofibrillary Tangle → aggregates (clumps/tangles) of hyperphosphorylated tau proteins

Diffuse loss of neurons