Memory, Learning & Amnesia

Question 1

Mention areas concerned with declarative memory

Answer 1

Hippocampus, medial temporal lobes of the brain, neocortex & prefrontal cortex

Question 2

Mention types of expilicit memory

Answer 2

Semantic memory: general memories, facts
Episodic memory: personal memories (events & experiences)

Question 3

Mention types of implicit memories & areas responsible

Answer 3

1. Priming: facilitation of recognition of words/objects. Neocortex
2. Procedural memory: skills & habits which become automatic & unconscious . Striatum & cerebellum
3. Associative learning: classical & operant conditioning. Amygdala & cerebellum
4. Non-associative: habituation & sensitisation, various reflex pathways

Question 4

Describe mechanism of storage of short & long term memories

Answer 4

S, involves transiet modifications in functions of preexisting synapses, such as altering amount of NT released or temoprarily inc responsiveness of the post-synaptic cell to NT
L, involves relatively permenant functional/structural changes as synapse/new protein formation such as: inc vesicle release sites, inc transmitter vesicles, inc presynaptic terminals, changes in structure of dendritic spines that permit transmission of stronger signals.

Question 5

Compare site of storage of short & long-term memory

Answer 5

S, stored in frontal lobe, explicit encoded in hippocampus
L, various parts of neocortex

Question 6

Define working memory

Answer 6

Form of short-term memory that keeps info available usually for very short periods while the individual plans actions based on it. Prefrontal cortex is its site of operation

Question 7

Define posttetanic stimulation, its mechanism

Answer 7

It is increase in the post-synaptic response following stimulation of presynaptic neuron by brief tetanizing train of stimuli
Accumulation of Ca in presynaptic neuron by tetanizing stimulus resulting in increased release of neurotransmitter

Question 8

Define habituation, its mechanism

Answer 8

It is decreased responsiveness to reptitive presentations if neutral stimulus
Gradual inactivation of Ca++ channels in presynaptic neurons by repeated stimulation so intracellular Ca++ dec and dec release of NT

Question 9

Define sensitization

Answer 9

Prolonges occurence of augmented postsynaptic response following stimulus to which one has become habituation once to more to being associated with noxious stimulus

Question 10

Describe mechanism of sensitization

Answer 10

Noxious stimulus causes serotonin release frim facilitatory interneuron on presynaptic terminal, serotonin receptor on sensory terminal membrane causes activation of adenyl cyclase causing inc formation of cAMP. This results in K+ channel blockade, resulting in prolonged action potential in synaptic terminals with more Ca++ influx and inc transmitter release.

Question 11

Describe mechanism of LTP

Answer 11

Multiple mechanisms by which LTP can occur, some are dependent on changescin the NMDA receptor and some are indeoendentof NMDA. It is initiated by inc IC Ca++ in either presynaptic or postsynaptic neuron.

Question 12

Describe mechanism & value of LTD

Answer 12

M, produced by slower stimulation of presynaptic neurons and is associated with a smaller rise intracellular Ca++ within postsyn neuron than that which occurs with LTP
V, mechanism of learning in cerebellum

Question 13

Compare causes of anterograde & retrograde amnesia

Answer 13

A, atherosclerosis, old age & lesions of hippocampus or medial temporal lobe
R, brain concussion, anesthesia, electroshock therapy

Question 14

NT affected by alzheimer is…..

Answer 14

Acetylcholine

Question 15

Compare classical & operant conditioning

Answer 15

C, conditioned reflex is reflex response to neutral stimuli. It involves repitive pairing of conditioned stimulus to unconditioned stimulus
O, it is the use of consequences to modify occurrence of behaviour. It involves applying reinforcement or punishment after behviour.