Max Planck Institute talk on learning rules

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Elements of synaptic learning rules
Sam Wang Princeton University synapse.princeton.ed
u
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Plasticity is usually measured across many
synapses
what are its properties at single synapses?
30,000 synapses
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CA3-CA1 synapse of hippocampus
Rich history of extracellular and single-cell
recording The cell biology and plasticity
literature is vast One synapse per connection Has
AMPA, NMDA, mGluR,
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Potentiation and depression events are
symmetrically sized
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Binary transitionsin single synapses
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Unitary events can account for the time course of
plasticity
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Calmodulin-dependent protein kinase II a
molecular switch
J. Lisman, H. Schulman, and H. Cline
(2002) Nature Rev. Neurosci. 3175
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Plasticity occurs in sudden steps
OConnor, Wittenberg and Wang (2005) PNAS 1029679
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The starting distribution of CA3-CA1 synapses
gt1 Hz
gt10 Hz
gt10 Hz
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Ensemble learning rules
Daniel OConnor Gayle Wittenberg J.
Neurophysiol. 2005 941565 PNAS 2005 1029679 J.
Neurosci. 2006 266610
L.F. Abbott and S.B. Nelson (2000) Nat. Neurosci.
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During active exploration, CA1 neurons fire
repeated bursts
Huxter et al. (2003) Nature 425828
Wittenberg Wang 2006
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Components of bidirectional plasticity
The potentiation rule
Requires postsynaptic bursts Requires high
frequency pairings
The depression rule
Broad timing-dependence Requires prolonged pairing
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Complications

• Spreading plasticity
• Priming
• Homeostatic plasticity
• Subcellular instruction

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Cerebellum the other gray meat
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Functional roles for the cerebellum
Motor coordination
Sensory surprise / error signals
Sensory teaching signal
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Cerebellar circuitry
Inputs Inferior olive gt Climbing fiber -gt
Purkinje cells Mossy fiber input -gt granule
cells -gtPurkinje cells Output Purkinje
cells-gtdeep nuclei
Dmitry Sarkisov
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Confocal
Two-photon
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Imaging neural activity in the intact cerebellum
Sullivan, Nimmerjahn, Sarkisov, Helmchen and Wang
(2005) J. Neurophysiol.
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Calcium responses in Purkinje cell dendrites
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In vivo ensemble coding - unpublished
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Wang laboratory and collaborators
Optical physiology and synaptic plasticity Eugene
Civillico, Tycho Hoogland, Bernd Kuhn, Eve
Schneider, Megan Sullivan, X. Richard Sun, H.
Megan Lee Lausanne Fritjof Helmchen, Werner
Goebel Max Planck Maz Hasan Princeton S. Jane
Flint, Lynn Enquist, David Tank, Dan
Dombeck RIKEN Junichi Nakai
Support NIH, NSF, W.M. Keck Foundation, Human
Frontier Science Project, N.J. Governors
Council on Autism
http//synapse.princeton.edu