PSYC 251 Lecture Notes - Lecture 16: Recognition Memory, Retrograde Amnesia, Anterograde Amnesia
22 Jun 2018
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o Hebbian learning
"neurons that fire together, wire together"
When presynaptic action potential leads to postsynaptic action potential,
connection is strengthened
Simple but powerful principal
(Eg)
training images (original image)
retrieval cue (degrader version of image)
recalled image (reconstruction is similar/ yet minimal noise
appears)
Long-Term Potentiation
Increase in synaptic strength
Exhibits necessary properties for Hebbian learning
Found in hippocampus (and other brain areas)
Early LTP
o Increased number of presynaptic release of
neurotransmitter
o Increased number of postsynaptic receptors
Late LTP
o Increased number of dendritic spines and synapses
All that is wrog with LTP
o If synapses only strengthen, naural firing eill gorw out of
control.... so...
Long-Term Depression (LTD)
Opposite of LTP
o "neurons that fire apart wire apart"
When synaptic action potential does NOT lead to postsynaptic
action potential, connection is weakened
Reduction in neurotransmitter released, number of receptors, and
number of synapses
o Episodic Retrieval = Reconstruction
Retrial of episodic memories is reconstruction
Best guess based on...
Memory trace/ genes/ past experience/ internal state/
environmental context
Episodic Memory can be inaccurate due to:
semantic relatedness (DRM paradigm)
cultural experience
source misattributions (where memory came from)
pragmatic inferences
misleading post-event information
Retrieval of episodic memories is reconstruction (not an accurate
recording)
False Memory (LAB 6 Activity)
