Theme 5: Memory and the changing brain Flashcards
hebbian learning
learning through strengthening connections
neurons that fire together, wire together –> explain
if neurons often fire together –> increased probability than when neuron A is activated, neuron B will become active too
long term potentiation
more effective synapse transmission = stronger response to same stimulus –> lasts a long time
long term depression
synaptic transmission becomes less effective as a result of recent activity = weaker response to similar stimulus
role hippocampus in memory
- critical for episodic memory (rats weren’t able to form episodic memory about a maze)
prediction of recall using fMRI
incidental learning task –> found more activity in medial temporal lobe for words that would be recalled
levels of processing effect in brain areas:
same brain areas are active in different levels of processing, however stronger activation during deep processing
distinguishing true from false episodic memories
parahippocampal cortex responds more strongly to ‘true’ episodic memories
robots gradient
in retrograde amnesia: more memory loss for events that occurred shortly before the damage than a longer time before
standard consolidation theory
first hippocampus & medial temporal lobe structures are involved in consolidation –> over time cortex become independent in retrieval
subcortical structures involved in episodic and semantic memory
-basal forebrain produces acetylcholine –> help hippocampus word effectively
-basal forebrain connects to diencephalon (thalamus, hypothalamus, mammillary bodies) through the fornix
-basal forebrain receieves oxygen from ACoA (anterior communicatory artery) –> aneurysm in ACoA causes anterograde amnesia (because hippocampus doesn’t receive neuromodulators anymore)
confabulations + possible cause
highly detailed false memories (basal forebrain damage) –> seems to be a source monitoring error
korsakoffs
-deficiency in thiamine (b vitamin) commonly seen in alcoholics
-causes confabulations and disorientations
dementia
impairments in thinking, commonly memory but no impairment to consciousness
alzheimer’s
-causes
-symptoms
-brain damage?
-neuronal loss, neurofibrillary tangles (inside) & amyloid plaques (outside)
-symptoms: problems with central executive, ribots gradient in memory loss, usually most damage to episodic but also semantic in the end
parkinson’s
-damage to neurons in basal ganglia + substantia nigra + disruption in dopamine processing
-motor problems + WM problems, ribots gradient for EM + issues with locating events in time /correct sequence of information
huntington’s
- basal ganglia & caudate nucleus damage
- motor movement impairment, problems with central executive more uniform memory loss over time
multiple sclerosis
- demyelination of neurons, damage to hippocampus
- muscle control problems and possibly memory loss
amnesia
memory loss
organic amnesia
amnesia as a result of organic brain damage
retrograde amnesia
loss of memories prior to incident
anterograde amnesia
loss of ability to store new memories / memory loss after incident
transient global amnesia
complete memory loss for a short period of time
semantic amnesia
inability to retrieve semantic knowledge
anomia
difficulty recalling word meaning (can be specific category of words)
apraxia
difficulty with how objects are used
aphasia
loss of ability to use language (comprehend/produce)
prosopagnosia
failure to recognise faces
psychogenic amnesia
amnesia with a psychological cause
dissociative amnesia
inability to remember segment of life
dissociative fugue
forgetting fundamental aspects of identity
Maguire et al: London taxi drivers & bus driver mri study
-goal: investigating effects of self motion, driving experience, stress on grey matter volume in taxi/bus drivers
- hypothesis: difference in grey matter volume is indicative of plasticity due to spatial demands placed on hippocampus
- method: MRI scan, loads of tests, using VBM to analyse grey matter volume
-RESULTS: more grey matter volume in posterior hippocampi, less volume in anterior hippocampi
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