Post on 23-Jan-2016
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Memory: the processes through which learned information is stored
Learning: the acquisition of an altered behavioral response due to an
environmental stimulus
Recall: the conscious or unconscious retrieval process through which this
altered behavior is manifest
Suggested Reading
• The Seven Sins of Memory by Daniel Schacter
• Mechanisms of Memory by David Sweatt• Grain Brain by David Perlmutter• Memory From Mind to Molecules by
Squire and Kandel
Neuron
Marina Chicurel and Christopher DeFranceo, The Inner Life of Neurons: An empire of semi-independent domains, The Harvard Mahoney Neuroscience Institute Letter: On The Brain, Vol. 4 (Spring, 1995), http://www.med.harvard.edu/publications/On_The_Brain/Volume4/Number2/SP95In.html
Neurons shapes and sizes from Univ. of Washington
Ion Channels
John Travis, Channel Surfing: Atomic-resolution snapshots illuminate cellular pores that control ion flow, Science News Online, Vol. 161 (March 9, 2002), http://www.sciencenews.org/articles/20020309/bob8.asp
Christof Koch, Biophysics of Computation: Information Processing in Single Neurons Oxford Univ. Press, Oxford, 1999, p. 7
Action Potential
adapted from J. Timothy Cannon, http://academic.uofs.edu/faculty/cannon/sp/02/ActionPotential.html, retrieved 3/30/04
http://www.blackwellpublishing.com/matthews/channel.html
Synapse
Dale Purves, George Augustine, David Fitzpatrick, Lawrence Katz, Anthony-Samuel LaMantia, James McNamara, and Mark Williams, Neuroscience, Sinauer Associates, Sunderland, Massachusetts, 2001, p. 142.
Cartoon
Expression of LTP• possible presynaptic mechanisms
– increased probability of transmitter release in response to a presynaptic action potential
– more transmitter released due to more sites of release – more transmitter released due to increased size of vesicles
containing neurotransmitter – a presynaptic mechanism requires a retrograde messenger (e.g.
nitrous oxide) to signal postsynaptic activity to the presynaptic terminal
• possible postsynaptic mechanisms – increased sensitivity to transmitter due to more postsynaptic
receptors for the neurotransmitter – increased sensitivity to transmitter due to increased
conductance of individual receptors • evidence points to a combination of both possibilities
Glu
Reuptake
Retrograde Signal
Presynaptic = Altered• Neurotransmitter amount in vesicles• Number of vesicles released• Kinetics of release• Glutamate reuptake• Probability of vesicle fusion
Postsynaptic = Altered• Number of AMPA receptors• Insertion of AMPA receptors• Ion flow through AMPA channels• Membrane electrical properties
Additional possibilities include changes in number of total synaptic connections between two cells
Membrane Properties
Release
Binding
Potential Sites of Synaptic Modification in LTP
ReleaseProcess
*PKC
AMPAR
NMDAR
Phosphorylation& Insertion
Ca++
RetrogradeMessenger?
*CaMKII
*PKMzeta
*PKC
Synaptic Tag
K+ Channels
Protein Synthesis
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* = Persistently Activated
CytoskeletonChanges
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Mechanisms for E-LTP
Activity-dependent Regulation of Gene Expression
How to reduce chances of Dementia and Alzheimer’s
• Diet – low calorie, high fat, high protein, low carb, high Omega-3 low Omega-6, blueberries, anti-oxidants
• Physical activity• Mental activity• Cholesterol levels – high cholesterol
good?• Hormone levels
Need volunteers
• 2-3 actors• 1 still photographer• 1 video photographer• Need to be here 30 minutes early next
week
Sins of Memory (Omission)
• Transience – weakening or loss of a memory over time
• Absent-mindedness – info not registered due to distraction
• Blocking – search for info we know, but can’t retrieve
Sins of Memory - Commission
• Misattribution – assigning a memory to the wrong source
• Suggestibility – memory implanted as a result of suggestions
• Bias – influence of current knowledge and beliefs on memory
• Persistence – repeated recall of disturbing memory that we would rather forget