Memory and Cognition

Question 1

what does cognition relate to?

Answer 1

highest order of brain function and relates to behaviour that deals with thought processing ie make sense of a stituation

Question 2

what is neuronal plasticity?

Answer 2

ability of central neurons to adapt their neuronal connections in responses to “learning” experiences.

Question 3

where are memories formed?

Answer 3

the limbic system

Question 4

what behaviour is the limbic system responsible for?

Answer 4

instinctive behaviour, eg drives for thirst, sex, hunger etc. but also important in emotive behaviour which in turn are drive by seeking reward or avoiding punishment

Question 5

why are reward and punishment central aspects to learning?

Answer 5

They form the “affective components” of sensory experiences. Motivation to learn comes from gaining a reward or avoiding a “punishment”. Gives a task significance.

Question 6

which of our experiences are barely remembered?

Answer 6

Experiences that are neither rewarding or punishing (insignificant experiences)

Question 7

what is the limbic system responsible for in relation to memory?

Answer 7

selecting what experiences are stored in memory (based on the significance of the event)

Question 8

where does almost all sensory information go through?

Answer 8

hippocampus, which in turn relays information to other limbic system structures.

Question 9

what is the hippocampus central for?

Answer 9

learning and the formation of memories

Question 10

what occurs when the hippocampus is damaged?

Answer 10

immediate (sensory) memory (seconds in length) and intact long-term memory (from time before damage), but are unable to form new long-term memories-Anterograde amnesia

Question 11

describe Immediate or Sensory memory

Answer 11

a few seconds. Describes the ability to hold experiences in the mind for a few seconds. Based on different sensory modalities. Visual memories decay fastest (<1s), auditory ones slowest (<4s).

Question 12

describe Short-term memory

Answer 12

seconds - hours. Often called Working Memory. Brain’s “post-it note”. Used for short term tasks such as dialling a phone number, mental arithmetic, reading a sentence. Associated with reverberating circuits.

Question 13

describe Intermediate long-term memory

Answer 13

hours to weeks e.g. what you did last weekend. Associated with chemical adaptation at the presynaptic terminal.

Question 14

describe Long-term memory

Answer 14

hours to lifetime. e.g. where you grew up and your childhood friends. Associated with structural changes in synaptic connections.

Question 15

how does short-term memory work?

Answer 15

is an electrical phenomenon. It depends on maintained excitation from reverberating circuits i.e. they need to be constantly refreshed.

Question 16

what occurs to the reverberation over time if deemed significant?

Answer 16

eventually this reverberation results in consolidation of the memory in long term memory storage

Question 17

what occurs to the reverberation over time if deemed insignificant?

Answer 17

reverberation fades and no consolidation occurs

Question 18

what is Retrograde amnesia?

Answer 18

can’t remember events leading up to the injury, although recall of events that happened a long time ago is usually unaffected, probably because they are better rehearsed and more deeply ingrained
often presents with anterograde amnesia

Question 19

if only the thalamus is damaged, and the hippocampus spared, what type of amnesia is seen?

Answer 19

retrograde amnesia is seen. Suggests thalamus is required for “searching” our existing memory bank.

Question 20

how does Intermediate Long-Term Memory work?

Answer 20

Involves chemical changes in presynaptic neuron:

Increasing Ca++ entry to presynaptic terminals, increases neurotransmitter release and hence “strengthens” the synapse.

Question 21

how does Long-Term Memory work?

Answer 21

Involves structural changes at synapses:
Increase in NT release sites on presynaptic membrane.
Increase in number of NT vesicles stored and released.
Increase in number of presynaptic terminals

Question 22

what is Long Term Potentiation?

Answer 22

greater change in graded membrane potential in the post-synaptic cell (EPSP) which “strengthens the synapse”
(occurs along with structural changes at synapses in long term memory)

Question 23

what are the two types of long-term memory?

Answer 23

Declarative or Explicit Memory

Procedural/ Reflexive/Implicit Memory

Question 24

describe Declarative Memory

Answer 24

Abstract memory for events (episodic memory) and for words, rules and language (semantic memory).
Is based mainly in the hippocampus

Question 25

describe Procedural Memory

Answer 25

Acquired slowly through repetition. Includes motor memory for acquired motor skills such as playing tennis, and rules based learning such as, in the UK, always driving on the left.
Is based mainly in the cerebellum (independent of hippocampus)

Question 26

what does consolidation require?

Answer 26

takes time (hours/days)
requires attention

Question 27

what occurs to “new memories”

Answer 27

“coded” then stored in the sensory and association areas of the cortex

Question 28

what does coding of new memories result in?

Answer 28

new memories being stored alongside other existing memories the brain deems similar.

Question 29

which part of the brain assess the significance of an event in short term memory?

Answer 29

The frontal cortex and its association with the reward/punishment centres in the limbic system

Question 30

what does the frontal cortex do if an experience is considered useful?

Answer 30

“gates” the Papez circuit

ie the experience is allowed through where it continues consolidation

Question 31

describe the papez circuit

Answer 31

hippocampus, to mammillary bodies, to anterior thalamus, to cingulate gyrus and back to hippocampus

Question 32

Reverberating activity then continues where after the papez circuit?

Answer 32

the frontal cortex then the sensory and association areas until the consolidation process is complete.