Memory and Cognition Flashcards
what is cognition (simplified)?
integration of all sensory information to make sense of a situation
what are association areas?
areas that integrate information from multiple sources
what is the function of the hippocampus?
formation of memories
what stores memories?
the cortex
what is the function of the thalamus?
it searches and accesses memories
what makes up the limbic system?
> cingulate gyrus
thalamus
hippocampus
amygdala
what is the link between emotions and ANS responses?
hypothalamus
what is responsible for instinctive or emotional behaviour?
the limbic system
what drives emotional and instinctive behaviour?
seeking reward or punishment
what is the effect of electrically stimulating reward areas of the limbic system in conscious patients?
there are intense feeling of well being, euphoria and sexual arousal
by stimulating what areas of the limbic system gives rise to feelings of terror, anger or pain?
punishment areas
describe the effect of bilateral hippocampal damage
there is immediate memory loss (seconds in length) and intact long term memory (from the time before the damage) but are unable to form new long term memories.
reflex memory is intact.
what is immediate/sensory memory?
> lasts a few seconds
describes the ability to hold experiences in the mind for a few seconds
visual memories decay fastest
auditory memories decay slowest
describe short term memory
> seconds-hours
used for short term tasks (dialling a number)
associated with reverberating circuits
describe intermediate long term memory
> hours-weeks
what you did last weekend
associated with chemical adaption at the presynaptic terminal
describe long term memory
> lifelong
> associated with structural changes in synaptic connections
describe the reverberating circuits in short term memory
each synapse in the circuit is excitatory so a brief excitatory stimulus at A causes a long lasting neuronal activity in B as the neurons continue to excite all neurons in the pathway.
what happens if memory in a reverberating circuit is deemed significant?
the reverberation results in consolidation of the memory in long term memory storage
what happens if the reverberation is deemed insignificant?
the reverberation fades and no consolidation occurs
what happens if the reverberation in short term memory is disrupted?
there is memory loss - amnesia
what is anterograde amnesia?
the inability to form new memories
what is retrograde amnesia?
inability to access old memories
when may only retrograde amnesia be seen?
if only the thalamus is damaged and the hippocampus spared
what chemical changes are seen in presynaptic neurons in intermediate long-term memory?
> increased Ca++ entry to presynaptic terminals
> increased neurotransmitter release
what are the structural changes that occur in long term memory formation?
> increase in neurotransmitter release sites on presynaptic membrane
increase in number of neurotransmitter vesicles stored and released
increase in number of presynaptic terminals
what is observed in the post synaptic cell in long term memory?
increased amplitude in graded membrane potential
what are the two main types of long term memory?
> declarative/explicit
> procedural/reflexive/implicit
describe declarative/explicit long term memory
abstract memory for events (episodic) and for words, rules and language (semantic).
based in the hippocampus
describe procedural/reflexive/implicit memory
this is required slowly through repetition including motor memory and rules based learning.
based mainly in the cerebellum
describe the consolidation process
> takes time
strengthening of synaptic connections through repetition
memory exists as electrical activity so is vulnerable to being wiped out
requires attention
what does coding of memories result in for their storage?
them being stored alongside other existing memories the brain deems to be similar
describe the papez circuit
cingulate gyrus > hippocampus > mammillary bodies > anterior thalamus
between what does reverberating activity continue between until consolidation occurs?
> papez circuit, frontal cortex, the sensory and the association areas
what is korsakoffs syndrome?
chronic alcoholism leads to vitamin b1 deficiency so there is damage of the limbic system and consolidation of memory is impaired
what is lost in alzheimers disease?
cholinergic neurons throughout the brain including the hippocampus
what do subject derived of REM sleep show?
significant impairment of memory consolidation for complex cognitive tasks
