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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Dear colleagues,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>I would like to bring to your attention our recent paper on experiments
and models on the Ca2+ dependence of LTD: <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>Ca2+ Requirements for Cerebellar Long-Term Synaptic Depression: Role
for a Postsynaptic Leaky Integrator<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>Neuron, Vol 54, 787-800, 07 June 2007<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>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,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>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.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><a
href="http://www.neuron.org/content/article/abstract?uid=PIIS0896627307003716">http://www.neuron.org/content/article/abstract?uid=PIIS0896627307003716</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>--</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Fidel Santamaria, PhD</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Assistant Professor</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Department of Biology</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>One UTSA circle</span></font><o:p></o:p></p>
<p class=MsoNormal><st1:PlaceType w:st="on"><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>University</span></font></st1:PlaceType><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> of <st1:PlaceName
w:st="on">Texas</st1:PlaceName> at <st1:City w:st="on"><st1:place w:st="on">San
Antonio</st1:place></st1:City>,</span></font><o:p></o:p></p>
<p class=MsoNormal><st1:place w:st="on"><st1:City w:st="on"><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>San Antonio</span></font></st1:City><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>, <st1:State
w:st="on">TX</st1:State> <st1:PostalCode w:st="on">78249</st1:PostalCode></span></font></st1:place><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Office: (210) 458-6910</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><a href="http://bio.utsa.edu/faculty/santamaria.html">http://bio.utsa.edu/faculty/santamaria.html</a></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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