Lec 11

Question 1

H.M patient

Answer 1

had epilepsy seizures focalised in medial temporal lobes, had a lobectomy removing hippocampus and amygdala, suffered memory loss.

Question 2

Amnesia

Answer 2

retrograde amnesia = deficits in memory prior to the surgery
anterograde amnesia = deficits in ability to form new memories in STM, or inability to transfer into LTM

Question 3

Digit Span + 1 test

Answer 3

recall five digits, each time remembered add 1 more number to the set. H.M had bad performance, averages is 15/25

Question 4

Block tapping test

Answer 4

examiner taps blocks in an order for 9 blocks, H.M could not match average of 6 taps

Question 5

mirror drawing test (impilict memory)

Answer 5

trace boundaries of shape watching mirror of hand, do it 10 times per day for 3 days, reduction in errors show H.M sustained some memory, but had no recall of actually doing the drawings on previous days

Question 6

incomplete pictures test.

Answer 6

five sets of pictures containing same objects but differ in degree of completion, determine level of completeness, repeat after 1 hour, non-impaired people identify pictures at lower completeness level on second run.

Question 7

pavlovian conditioning

Answer 7

H.M learned eye-blink conditioning task, rate of learning slower than normal but retained. after two years showed signs of retained conditioned response but could not remember doing the memory task

Question 8

contribution of H.M case

Answer 8

revealed role of medial temporal lobe in memory, support different codes of memory STM/LTM/remote memory. Understood amnesic patients may show implicit memory but limited explicit memory

Question 9

medial-temporal lobe amnesia

Answer 9

patients who preserve intellectual functioning with damage to medial temporal lobe. difficulty in forming explicit memories, but retain ability to form implicit memories. Can only repeat task under same conditions it was learned in.

Question 10

semantic / episodic memory

Answer 10

semantic = general facts / info
episodic= explicit memories for specific life moments. medial temporal lobe damage causes deficits in episodic.

Question 11

Korsakoff’s amnesia

Answer 11

memory disorder due to excessive alcohol for prolonged period, causing thiamine deficiency, confusion, personality chance, brain dysfunction, organ dysfunction. causes amnesia similar to medial temporal lobe damage, however Korsakoff damage is diffuse and hard to identify, most patients suffer damage to mediodorsal thalamic nuclei

Question 12

Alzheimer’s amnesia

Answer 12

alzheimer in early stages cause mild memory deficits, progressed is deterioration of memory and verbal abilities. shows anterograde and retrograde amnesia, implicit for verbal and perceptual memory is degraded.

Question 13

post-traumatic amesia

Answer 13

closed head TBI’s most common cause of amnesia. Coma = unconscious states following head blow causing retrograde amnesia for events leading up to concussion. Then confusion and anterograde amnesia for events during state of confusion.

Question 14

electroconvulsive shock and consolidation

Answer 14

Brief intense seizure in the brain administered via electrodes. Used for depression treatment but erases memories that have not undergone consolidation. Some memories can undergo consolidation for life.

Question 15

Hippocampus and ischemia

Answer 15

patients suffering global cerebral ischemic suffer medial temporal lobe amnesia. Case found after ischemic death, damage to pyramidal cell layer of hippocampus

Question 16

delay-matching test / mumby box

Answer 16

monkey presses button to obtain food and door closes, after delay period monkey presented with same button and different buttons and must remember not to press sample button if it wants food. medial temporal lesion perform worse at greater delay times. test showed amnesia due to temporal lobe damage is entirely due to hippocampus. mumby box = same but for rats.

Question 17

hippocampus / hippocampus place cells

Answer 17

bilateral lesions of hippocampus disrupt performance on memory for spatial location. only one structure for memory. Place cells respond to very specific areas of environment. When in new environment place cells do not have place field for that environment. Some cells also fire for temporal aspects of experience influencing learning about social organisation. hippocampus = generating cognitive map.

Question 18

Jennifer aniston neurons / concept cells

Answer 18

concept cells fire for particular person recording from medial temporal lobes. Neurons fire to image, printed name or sound of voice. Neuron may also fire to very similar concepts to that neuron.

Question 19

engram cells

Answer 19

neuron undergoing persistent change in response to experience, when activated or inhibited, retrieval of original experience is triggered or suppressed respectively. In hippocampus, medial temporal cortex, mediodorsal nucleus, thalamus and basal forebrain

Question 20

inferotemporal cortex in memory

Answer 20

responsible for complex visual function, memories of visual input

Question 21

amygdala in memory

Answer 21

encodes emotionally charged memories, does not store but may strengthen these emotional memories

Question 22

prefrontal cortex in memory

Answer 22

memories for tasks involving series of responses e.g. recipe

Question 23

cerebellum in memory

Answer 23

memory for sensorimotor tasks

Question 24

striatum in memory

Answer 24

memory for relationships between stimuli and responses, basis of habit formation

Question 25

long term potentiation (LTP)

Answer 25

two or more neurons (assemblies) excited at same time and synapses repeatedly activated and chemistry of synapses become strengthened. long term learning based on develop of synaptic connections

Question 26

3 stages of LTP

Answer 26

induction = NMDA receptors for glutamate bind only respond of two events occur simultaneously and post synaptic neurons must already be partially depolarised. maintenance and expression = changes in presynaptic and post synaptic neurons

Question 27

inducing / measuring LTP

Answer 27

low intensity current delivered to neuron projection in hippocampus and recorded.

Question 28

non-synaptic mechanisms of learning and memory

Answer 28

oligodendrocytes modulate myelination of axons in response to experience. Myelin sheath is not static, unmyelinated axons can be myelinated from oligodendrocytes. myelinated axons can have sheath removed, replaced, thinned/thickened, shortened/lengthened