remembering brain Flashcards
function-structure relationship
relationship between brain region and function = NOT 1 to 1
single function = many brain structures
brain structure = many functions
declarative memory brain region
medial temporal lobe
procedural memory brain area
basal ganglia and cerebellum
perceptual representation system brain area
perceptual and association neocortex
classical condition brain area
cerebellum
non-associative learning brain area
reflex pathways
episodic memory
mental time travel
create links between unrelated info to make an episode
time and place
episodic memory is the result of
associative learning
context of memory are associated and bound together
autobiographical memory contains
episodic and semantic memory
MTL areas
hippocampus parahippocampal gyrus - entorhinal cortex - perihinal cortex - parahippocampal cortex
hippocampus subdivided into
dendate gyrus subiculum cornu ammonis (CA) - CA1 +3 = largest and studied more - CA2+4 = smaller
info flow in MTL
sensory info converges in perihinal and parahippocampal cortex
> entorhinal cortex > hippocampus > entorhinal cortex + cortical areas of MTL
LOOP
info processed in all areas
extended MTL
thalamus and prefrontal cortex
HM deficit
couldn’t form new memories (anterograde amnesia)
couldn’t remember 2 years prior to surgery (retrograde amnesia)
deficit moving STM to LTM - bad at digit span test
HM could…
remember number if engaged WM and repeated it - good STM
improve at star tracing - intact implicit LTM
anterograde amnesia
deficit in learning new info
most common
retrograde amnesia
deficit in remember events before brain injury
both anterograde and retrograde amnesia
global amnesia
subsequent memory paradigm
evaluate how encoding leads to successful or unsuccessful memory formation
- record neural responses during encoding and recognition
Wagner et al (1998) brain region predictive of later remembered vs forgotten items
left ventrolateral prefrontal cortex
left medial temporal lobe
types of recognition memory
familiarity
recollection
familiarity
asked if object is old or new
no context
recollection
can classify object as old by recollecting additional info about context or other associative info
MTL in recognition memory - Eichenbaum et al
perihinal cortex = processes item representation = familiarity
parahippocampal cortex = processes context (scene perception)
hippocampus = binds items to context via entorhinal cortex = recollection
Ranganath et al (2004) - recognition judgement and memory sourced decision in familarity and recollection
familiarity = high recognition judgement (there at encoding?), low memory sourced decision (which Q encoded with?)
recollection = high memory sourced decision
found activity in corresponding areas
familiarity - perihinal cortex
recollection - parahippocampal/hippocampus
brain area supporting recollection of objects
hippocampus
MTL regions supporting familiarity
objects, faces, scenes
perihinal cortex - objects
entorhinal cortex - objects and faces
parahippocampus - faces and scenes
amygdala - faces
alzheimer’s disease rehabilitation
focus on familiarity
entorhinal cortex and hippocapus damage first
- difficulty with recall and spatial memory
2 types of consolidation
synaptic
system
synaptic consolidation
faster - hours-days
structural changes in synaptic connections
learning of new info = more likely to have an AP going from one neuron to next
system consolidation
slower
denotes gradual shift from hippocampus to neocortical regions
2 theories of memory consolidation
- standard consolidation theory
- multiple trace theory
standard consolidation theory
hippocampus = temporary role in storing remote memories - binds elements of an episode
reactivation of hippocampal memory - every time memory retrieved strengthens connection between hippocampus and neocortex and connections within neocortex
- eventually becomes independent of hippocampus
Nestor et al (2002) demonstrating standard consolidation theory
- SD and AD
SD = damage in neocortical AD = damage in hippocampal
AD = recent memory impaired - relies on hippocampus SD = distant memory impaired - relies on neocortex
evidence from amnesia - standard consolidation theory
anterograde = no new memories as hippocampus damaged retrograde = older memories - neocortex (not affected) - recent memories - hippocampus - not consolidated (affected)
multiple trace theory
Nadel and Moscovitch (1997, 1998)
hippocampus never stops having an important role
older memories become more semantic like - transforming not transferring (no episodic detail)
- so following hippocampal damage - can be recalled without episodic detail
Ribot’s law
memory loss has a temporal gradient
more recent memories more likely to be lost than distant memories
in line with consolidation - distant memories undergone consolidation
HM and PZ show this
multiple trace theory explanation of temporal gradient
older memories reactived more times - causes new traces in hippocampus, MTL + neocortex
extent of damage isnt global so more likely to be preserved as more connections
evidence for multiple trace theory - fMRI pictures of personal experinces
Hippocampus was activated for remote and recent memories
degree of hippocampal activation was proportional to vividness of memory
spatial memory
hippocampus
food-storing birds = bigger hippocampus
london taxi drivers = bigger hippocampus
rats with no hippocampus = cant do water-maze to find platform
spatial memory cells
place cells - hippocampus
grid cells - entorhinal cortex
boundary cells - entorhinal cortex
