Learning and Memory

Question 1

What is the Information processing model

Answer 1

Theory that memory consists of multiple components and processes.

Question 2

What are the components and processes of the Information Processing Model?

Answer 2

Sensory input -> Sensory Memory -> Short Term Memory -> Long Term Memory

Question 3

What is sensory memory?

Answer 3

1. Immediate, initial recording of sensory info.
2. Large capacity
3. very short duration (~1-2 seconds)
4. reflects residual activity of sensory neurons.

Question 4

What is short term memory?

Answer 4

1. active “workspace” for conscious thought and reasoning
2. requires encoding from sensory memory and/or retrieval from LTM
3. Small capacity (~ 7items)
4. short duration (~30 sec)- longer with rehearsal
5. prefrontal cortex

Question 5

Long term memory

Answer 5

1. potential infinite capacity & duration
2. accessed via working memory (retrieval)
3. requires consolidation by limbic system (enhances REM sleep)
4. strengthened by frequent rehearsal (although details may change)
5. different subtypes distributed throughout the brain.

Question 6

What are some key questions concerning memory?

Answer 6

1. how is sensory information encoded into STM? (Attention)
2. Where and how does consolidation (STM to LTM) take place?
3. Where an how is LTM stored?
4. WHere and how is LTM stored?
5. Are there different types of LTM?

Question 7

What is retrograde amnesia?

Answer 7

1. Loss of memory for past events (i.e. prior to injury), typically limited to a short time period.
2. a temporary interruption of consolidation from STM to LTM (or ITM)
3. Caused by concussion, loss of consciousness, alcohol

Question 8

Anterograde Amnesia

Answer 8

1. loss of ability to retain new information (a permanent impairment of consolidation from STM to LTM)
2. Dues to bilateral damage to the limbic system, especially the hippocampus (medial temporal lobes). e.g. strokes, korsakoff’s syndrome
3. famous cases: H.M., Clive Wearing

Question 9

What have studies shown on anterograde amnesia?

Answer 9

1. amnesic show improvement on implicit skills- (mirror tracking, fragmented pictures)

Question 10

What is declarative (explicit) memory?

Answer 10

1. info acquired through learning
2. memory we are aware of accessing
3. requires intact limbic system

Question 11

Procedural (implicit) memory

Answer 11

1. memory shown through performance rather than conscious recollection
2. memory we are not aware of accessing

Question 12

Declarative Memory (semantic memory)

Answer 12

1. generalized memory of information

Question 13

Declarative Memory (episodic memory)

Answer 13

1. autobiographical memory

2. memory for events in time and place

Question 14

How does damage effect Declarative Memory

Answer 14

1. Frontal-parietal damage can selective impair episodic memory (source amnesia)
2. Semantic memory appears to be more widely distributed. (focal cortical lesions impair ability to name objects from specific categories)

Question 15

Procedural (non-Declarative memory

Answer 15

1. Stored in sam areas responsible for carrying out the behavior

• sensorimotor skills = basal ganglia, cerebellum, motor cortex
• classical conditioning = cerebellum
• emotional memory = amygdala

Question 16

Animal Lesions

Answer 16

general consistent with finding from humans

• hippocampal lesions impair performance , especially spatial memory
• cannot easily discriminate and explicit memory in animals

Question 17

What is Hebbs view on synaptic plasticity?

Answer 17

1. learning is dues to increases in synaptic strength
2. existing connections between simultaneously active neurons are strengthened (“Hebbian synapses”)- Neurons that fire together wire together

Question 18

What are the 4 mechanisms of synaptic plasticity

Answer 18

1. Changes in existing synapses (amount of NT or # of receptors)
2. changes in interneuron modulation (axo-axonal connections)
3. more or fewer synaptic contacts between neurons
4. rearrangement of synapses.

Question 19

What are the effects of behavioral intervention on synaptic plasticity (environmental condition)

Answer 19

Enriched environments produce:

• better learning & problem solving
• faster recovery from injury or malnutrition
• less age-related declines in memory

Question 20

What are the effects of behavioral intervention on synaptic plasticity (neurological changes)

Answer 20

1. increased amounts of AChE (more neural activity)
2. larger cortical volume & thickness
   - larger cell size
   - more dendritic branching
   - larger synaptic contacts

Question 21

What are the effects of behavrioal intervention on synaptic plasticity ( Habituation in aplysia)

Answer 21

1. a decrease in response to repeated presentation of a stimulus.
2. short term habituation- decreased release of NT at sensorimotor synapse.
3. Long term habituation- retraction of some synaptic terminals at sensorimotor junction.

Question 22

How was Long Term Potentiation discovered?

Answer 22

1. repeated high intensity stimulation of neurons in the perforant pathway of the rat hippocampus results in a prolonged pattern of elevated EPSPs in the mossy fibers (receiving neurons)

Question 23

What is the role of NMDA receptors on long term potentiation

Answer 23

1. at least 2 types of glutamate receptors:
   - AMPA: ionotropic Na+ channels
   - NMDA: ionotropic Ca++ channel blocked by Mg+

Question 24

What are some more roles of NMDA receptors on long term potentiation

Answer 24

1. repeated stimulation of AMPA receptors (Na+ channels) by Glu produces depolarization of post-syaptic cell
2. knocks Mg+ block out NMDA receptors, allowing Ca++ inside (when Glu is present)
3. Ca++ triggers activity of protein kinases.

Question 25

What is protein kinases?

Answer 25

1. cause increase in # of AMPA receptors on post-synaptic cell
2. trigger second-messenger system that enhances release of Glu in pre-synaptic cell

Question 26

What are conclusions we can draw from the role of NMDA receptors on long term potentiation?

Answer 26

1. synapse is strengthened

2. effects can last a long time

Question 27

What are other LTP mechanisms?

Answer 27

1. in some brain regions, LTP can occur when NMDA receptors are blocked by an antagonist
2. this LTP likely involves other types of Ca++ channels- LTP does not occure when all Ca++ channels are blocked

Question 28

What is classical conditioning?

Answer 28

1. a form of non-declarative learning in which as association is formed between two stimuli, such that they both produce the same (or similar) responses.

Question 29

What are eye blink conditioning in rabbits?

Answer 29

1. unconditioned stimulus (US): puff of air
2. unconditioned response (UR): reflexive eye movement
3. conditioned (learned) stimulus (CS): tone (paired with US)
4. conditioned (learned) response (CR): eye blink in response to CS (tone), timed to protect eye against puff of air

Question 30

What procedure was most effective in eye blink conditioning?

Answer 30

delay conditioning (CS precedes & overlaps US)

Question 31

What are the effects of brain lesions on eye blinking conditioning?

Answer 31

1. hippocampal lesions have negligible effects on delay conditioning.
2. cerebellar lesions prevent &/or abolish conditioned eye blinks, although the reflex is still present