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Dear Colleagues,

Preprints of two papers on spike timing-dependent synaptic plasticity
are available:

"Spike timing-dependent plasticity: The relationship to rate-based learning
for models with weight dynamics determined by a stable fixed-point",
A.N. Burkitt, H. Meffin, and D.B. Grayden, to appear in Neural Computation,
is available at
http://www.bionicear.org/people/burkitta/Burkitt_NC_2003.pdf

"How synapses in the auditory system wax and wane: Theoretical perspectives",
A.N. Burkitt and L.J. van Hemmen, to appear in Biological Cybernetics,
is available at
http://www.bionicear.org/people/burkitta/BurkittvH_BC_2003.pdf

Regards,

Tony Burkitt

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"Spike timing-dependent plasticity: The relationship to rate-based learning
for models with weight dynamics determined by a stable fixed-point",

A.N. Burkitt, H. Meffin, and D.B. Grayden, to appear in Neural Computation,

Abstract:
---------
Experimental evidence indicates that synaptic modification depends upon
the timing relationship between the presynaptic inputs and the output
spikes that they generate.  In this paper results are presented for
models of spike timing-dependent plasticity (STDP) whose weight dynamics 
is determined by a stable fixed-point.  Four classes of STDP are identified
on the basis of the time-extent of their input-output interactions.  The 
effect upon the potentiation of synapses with different rates of input is
investigated to elucidate the relationship of STDP with classical studies
of LTP/LTD and rate-based Hebbian learning.  The selective potentiation of
higher-rate synaptic inputs is found only for models where the time-extent
of the input-output interactions are ``input restricted'' (i.e., restricted
to time domains delimited by adjacent synaptic inputs) and that have a
time-asymmetric learning window with a longer time constant for depression
than for potentiation.  The analysis provides an account of learning dynamics
determined by an input-selective stable fixed-point.  The effect of
suppressive interspike interactions upon STDP are also analyzed and shown
to modify the synaptic dynamics.

http://www.bionicear.org/people/burkitta/Burkitt_NC_2003.pdf

===============================================
"How synapses in the auditory system wax and wane: Theoretical perspectives",

A.N. Burkitt and L.J. van Hemmen, to appear in Biological Cybernetics,

Abstract:
---------
Spike timing-dependent synaptic plasticity has recently provided
an account of both the acuity of sound localization and the
development of temporal-fea\-ture maps in the avian auditory system.
The dynamics of the resulting learning equation, which describes
the evolution of the synaptic weights, is governed by an unstable
fixed-point.  We outline the derivation of the learning equation
for both the Poisson neuron model and the leaky integrate-and-fire
neuron with conductance syn\-ap\-ses.  The asymptotic solutions of
the learning equation can be described by a spectral representation
based on a biorthogonal expansion.

http://www.bionicear.org/people/burkitta/BurkittvH_BC_2003.pdf
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Anthony N. Burkitt
The Bionic Ear Institute                
384-388 Albert Street
East Melbourne, VIC 3002
Australia

Email:  aburkitt at bionicear.org
http://www.bionicear.org/people/burkitta     
Phone: +61 - 3 - 9663 4453
Fax:   +61 - 3 - 9667 7518                                            
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