Section 7 Learning and Memory

I Learning

Learning: associative and nonassociative

The acquisition of knowledge or skill;

Associate and nonassociative learning

NonassociativeNonassociative

No paired stimulus/response

Habituation - becomes less responsive to repeated no-harmful stimuli

Sensitization - becomes more responsive – to repeated harmful stimulation

AssociativeAssociative

Paired stimulus/responseTwo basic types

– classical conditioning (two stimuli are paired; when the light shines ----- get food)

– operant conditioning (stimuli and response are paired; push lever = food

Psychological aspectsPsychological aspects

Classical conditioning requires that the learning have predictive value

Conditioned stimuli (no overt response) and unconditioned stimuli (gives an overt response)– not simply timing of events relative to each other– blocking phenomena (tone and light experiment)

tone does not add anything so not learned

– we can detect a positive correlation between two stimuli (efficiency of pairing)

– Extinction can occur over time (unpaired)

Psychological aspectsPsychological aspects

Operant conditioning (trial-and-error learning)– A predictive relationship between response and a

stimulus – behaviors that are rewarded tend to be repeated; those

that cause aversive consequences are not repeated – timing is important – must have predictive element

Learning involves forming Learning involves forming memoriesmemories

II MemoryII Memory

MemoryMemory

Memory is the storage and retrieval of information

The three principles of memory are:– Storage – occurs in stages

and is continually changing– Processing – accomplished

by the hippocampus and surrounding structures

– Memory traces – chemical or structural changes that encode memory

1. Stages of Memory1. Stages of Memory

The two stages of memory are short-term memory and long-term memory

Short-term memory (STM, or working memory) – a fleeting memory of the events that continually happen

STM lasts seconds to hours and is limited to 7 or 8 (not more than 12 items) pieces of information

Long-term memory (LTM) has limitless capacity

Basics relationshipsBasics relationships

Short term - limited capacity and duration (12 items, few minutes)Long term - more permanent; can be blocked by blocking protein synthesis

Transfer from STM to LTMTransfer from STM to LTM

Factors that affect transfer of memory from STM to LTM include:– Emotional state – we learn best when we are alert,

motivated, and aroused– Rehearsal – repeating or rehearsing material

enhances memory– Association – associating new information with old

memories in LTM enhances memory– Automatic memory – subconscious information

stored in LTM

Declarative (Explicit) or Nondeclarative (Implicit) Memory

1. Declarative - Explicit1. Declarative - Explicit

a. Semantic - general knowledge of the world

b. Episodic - knowledge of your own past experiences

2. Nondeclarative or Implicit2. Nondeclarative or Implicit- Procedural - learned skills or habitual responses, - classical conditioning

Declarative (Fact) memory:

–Entails learning explicit information

–Is related to our conscious thoughts and our language ability

–Is stored with the context in which it was learned

Nondeclarative (Skill) MemoryNondeclarative (Skill) Memory

Skill memory is less conscious than fact memory and involves motor activity

It is acquired through practiceSkill memories do not retain the context in which

they were learned

Structures Involved in Fact Structures Involved in Fact MemoryMemory

Fact memory involves the following brain areas:– Hippocampus and the amygdala, both limbic system s

tructures– Specific areas of

the thalamus and hypothalamus of the diencephalon

– Ventromedial prefrontal cortex and the basal forebrain

Figure 15.8a

Major Structures Involved with Skill Major Structures Involved with Skill MemoryMemory

Skills memory involves:– Corpus striatum – mediates the automatic connectio

ns between a stimulus and a motor response– Portion of the

brain receiving the stimulus (visual in this figure)

– Premotor and motor cortex

Figure 15.8b

3. Mechanisms of Memory3. Mechanisms of Memory

The engram, a hypothetical unit of memory, has never be elucidated

Changes that take place during memory include:– Neuronal RNA content is altered– Dendritic spines change shape– Unique extracellular proteins are deposited at synaps

es involved in LTM– Presynaptic terminals increase in number and size, a

nd release more neurotransmitter

4. FORGETTING4. FORGETTING

Forgetting as a result of Forgetting as a result of decay?decay?

Simple passage of Simple passage of time after learning time after learning has has minimalminimal effect on effect on retentionretention

Forgetting as a result of Forgetting as a result of interferenceinterference

Retroactive Retroactive InterferenceInterference

Current learning interferes with recall of Current learning interferes with recall of

previously learned materialpreviously learned material

Retroactive InterferenceRetroactive Interference

Learn Learn MemoryLearn Learn Memory A B LossA B Loss for Afor A

TimeTime

Proactive Proactive InterferenceInterference

Prior learning interferes Prior learning interferes with retention of new with retention of new informationinformation

Proactive InterferenceProactive Interference

Learn Learn MemoryLearn Learn Memory A B LossA B Loss for Bfor B

TimeTime

Retrograde and AnterogradRetrograde and Anterograde Amnesiae Amnesia

TimeTime

Retrograde AnterogradeRetrograde Anterograde

Head TraumaHead Trauma