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Lecture 24
Learning and Memory II
Memories
• Long term memory stored in cortex
• Information is processed for memory storage
in other brain regions (i.e hippocampus)
Long-term Potentiation
• Timothy Bliss and Terje Lomo (1973)
• Facilitation of synaptic transmission following
high-frequency electrical stimulation applied
to presynaptic neurons
Evidence for LTP and learning and
memory
• LTP can last for a long time
• LTP is dependent on presynaptic and
•
•
•
postsynaptic neurons firing
LTP can be elicited by stimulation that mimics
neural activity
LTP is demonstrated in hippocampus and
other areas that have been implicated in
learning and memory
Behavioral conditioning can produce LTP-like
changes (aplysia experiments)
Evidence for LTP and learning and
memory
• Drugs that influence learning, influence LTP
• Maximal LTP blocks learning, normal LTP
•
•
promotes learning and memory
Mutant mice that display no LTP don’t learn
well
LTP occurs at synapses that have been
shown to be involved in learning and memory
Protein kinases involved in LTP
• Protein kinase A (PKA)
• Protein kinase C (PKC)
• Calcium-calmodulin kinase (CaM Kinase or
•
CaMK)
Tyrosine kinase (TK)
Stages of memories
• Iconic
• Short-term
• Intermediate term
• Long term
Hypotheses for memory decline
• Disease (Alzheimer’s)
• Loss of neurons and/or neural connections
• Impairment of the cholinergic system
• Impaired coding by place cells
Preventing memory decline…?
• Lower glucocorticoids
• Infusion of NGF into the brain…?
• Live an enriched lifestyle