Section 7 Learning and Memory

I Learning

Learning: associative and nonassociative The acquisition of knowledge or skill; Associate and nonassociative learning

Nonassociative No paired stimulus/response Habituation - becomes less responsive to repeated no-harmful stimuli Sensitization - becomes more responsive – to repeated harmful stimulation

Associative Paired stimulus/response Two 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 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 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 memories

II Memory

Memory 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 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 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 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 - Explicit a. Semantic - general knowledge of the world b. Episodic - knowledge of your own past experiences 2. 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) Memory Skill memory is less conscious than fact memory and involves motor activity It is acquired through practice Skill memories do not retain the context in which they were learned

Structures Involved in Fact Memory Fact memory involves the following brain areas: – Hippocampus and the amygdala, both limbic system structures – 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 Memory Skills memory involves: – Corpus striatum – mediates the automatic connections 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 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 synapses involved in LTM – Presynaptic terminals increase in number and size, and release more neurotransmitter

4. FORGETTING

Forgetting as a result of decay?

Simple passage of time after learning has minimal effect on retention Simple passage of time after learning has minimal effect on retention

Forgetting as a result of interference

Retroactive Interference Current learning interferes with recall of previously learned material Current learning interferes with recall of previously learned material

Retroactive Interference Learn Learn Memory A B Loss A B Loss for A for ATime

Proactive Interference Prior learning interferes with retention of new information Prior learning interferes with retention of new information

Proactive Interference Learn Learn Memory A B Loss A B Loss for B for BTime

Retrograde and Anterograde Amnesia Time Time Retrograde Anterograde Retrograde Anterograde Head Trauma Head Trauma