[Comp-neuro] New paper on Ca+2 feedback in cerebellar LTD

[Fidel Santamaria]

Dear colleagues,

 

I would like to bring to your attention our recent paper on experiments
and models on the Ca2+ dependence of LTD: 

 

Ca2+ Requirements for Cerebellar Long-Term Synaptic Depression: Role for
a Postsynaptic Leaky Integrator

Neuron, Vol 54, 787-800, 07 June 2007

 

Keiko Tanaka,1 Leonard Khiroug,1,2 Fidel Santamaria,1 Tomokazu Doi,4
Hideaki Ogasawara,4,5 Graham C.R. Ellis-Davies,3 Mitsuo Kawato,4 and
George J. Augustine1,

 

Photolysis of a caged Ca2+ compound was used to characterize the
dependence of cerebellar long-term synaptic depression (LTD) on
postsynaptic Ca2+ concentration ([Ca2+]i). Elevating [Ca2+]i was
sufficient to induce LTD without requiring any of the other signals
produced by synaptic activity. A sigmoidal relationship between [Ca2+]i
and LTD indicated a highly cooperative triggering of LTD by Ca2+. The
duration of the rise in [Ca2+]i influenced the apparent Ca2+ affinity of
LTD, and this time-dependent behavior could be described by a leaky
integrator process with a time constant of 0.6 s. A computational model,
based on a positive-feedback cycle that includes protein kinase C and
MAP kinase, was capable of simulating these properties of Ca2+-triggered
LTD. Disrupting this cycle experimentally also produced the predicted
changes in the Ca2+ dependence of LTD. We conclude that LTD arises from
a mechanism that integrates postsynaptic Ca2+ signals and that this
integration may be produced by the positive-feedback cycle.

 

http://www.neuron.org/content/article/abstract?uid=PIIS0896627307003716

 

--

Fidel Santamaria, PhD

Assistant Professor

Department of Biology

One UTSA circle

University of Texas at San Antonio,

San Antonio, TX 78249

Office: (210) 458-6910

http://bio.utsa.edu/faculty/santamaria.html

 

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