topic 9

Question 1

what is the engram?

Answer 1

a unit of cognitive information embedded in a physical substance

Question 2

how did karl lashley test for the engram?

Answer 2

damaged certain regions of a rats brain to see if it damages its memory of how to get through a maze

he found that the larger the area of damage, the more errors the rat made when going through the maze

with this he coined the law of mass action or equipotentiality, meaning that memory loss is a result of how much of the whole brain is damaged and not due to to loss of any particular area

Question 3

outline Korsakoffs syndrome

Answer 3

korsakoffs syndrome causes profound memory loss and involves a small lesion to a tiny part of the brain called mamilary bodies

Question 4

outline the case study of HM

Answer 4

• HM had profound amnesia
• this arose due to damage in his brain that occured in surgery to treat epilepsy
• his medial temporal lobe was removed
• this suggested that the hippocampus was a key structure in declarative memory

Question 5

what is anterograde amnesia?

Answer 5

inability to form memories

Question 6

what was milners findings about HM and procedural memory?

Answer 6

• HM was able to improve at skills requiring procedural memory (mirror drawing task) how ever he could not remember ever having practiced them
• this suggests that the medial temporal lobe structures that were removed seem only to be involved in consciously available declarative memory

Question 7

what is the difference between declarative and non declarative

Answer 7

declarative/explicit = consciously available
non-declarative/implicit= not consciously available

Question 8

what are two types of declarative memory?

Answer 8

semantic

eposidic

Question 9

what are two types of non declarative memory?

Answer 9

associative (e.g conditioning)
non associative (e.g habituation)

Question 10

what part of the brain is motor learning involved in?

Answer 10

cerebellum

Question 11

what part of the brain is habituation and sensitisation involved in

Answer 11

reflex pathways and neocortex

Question 12

what part of the brain does emotional learning often involve?

Answer 12

amygdala

Question 13

why is alplysia californica used in neuroscience research

Answer 13

• it is a marine mollusk
• it has enormous neurons that are easily accessible to electrodes
• studies of habituation in this organism found that the animal stopped producing an electrical response to a waterjet over time. this habituation was found to be because of reduced transmitter release from the presynaptic sensory neuron

Question 14

what are 5 reasons for using the mouse as an animal model of memory and learning

Answer 14

• mammal so closely related to humans
• produces large litters
• short gestation time
• matures quickly
• ameaneable to genetic engineering

Question 15

how can we use genetic engineering to study memory in mice?

Answer 15

• candidate molecular mechanisms in learning and memory can be enhanced or suppresed
• temporally and spatially conditional knockdown systems can be used
• cell type and activity dependent markers can be expressed
• opto-genetic/chemo-genetic actuators can be expressed
• diseases with known genetic cause can be modelled

Question 16

what is second order conditioning

Answer 16

e.g rewarding an animal with food and then training them to associate this food reward with a click and then using the click to train animals

Question 17

how are proteins related to memory consolidation?

Answer 17

New proteins are expressed to support memory consolidation

if we block protein translation in certain situations we can block lasting memory

if we block transcription we can also block long lasting forms of synaptic plasticity and memory

blocking these processes doesnt block short term memory

delivering a protein synthesis inhibitor in rats stopped them from developing long term memory relating to their fear conditioning
delivering the same inhibitor later during retrieval of the memory then led to the memory erasing