X-Message-Number: 13239
Date: Thu, 10 Feb 2000 17:28:33 -0500
From: Jan Coetzee <>
Subject: Trends in Neurosciences

Trends in Neurosciences, 2000, 23:2:53-57


     The recent advent of novel high-resolution imaging methods has
created a
     flurry of exciting observations that address a century-old
question: what are
     biological signals that regulate formation and elimination of
dendritic spines?
     Contrary to the traditional belief that the spine is a stable
storage site of
     long-term neuronal memory, the emerging picture is of a dynamic
     that can undergo fast morphological variations. Recent conflicting
reports on
     the regulation of spine morphology lead to the proposal of a
     hypothesis for a common mechanism involving changes in postsynaptic

     intracellular Ca2+ concentration, [Ca2+]i: a moderate rise in
[Ca2+]i causes
     elongation of dendritic spines, while a very large increase in
[Ca2+]i causes
     fast shrinkage and eventual collapse of spines. This hypothesis
provides a
     parsimonious explanation for conflicting reports on
activity-dependent changes
     in dendritic spine morphology, and might link these changes to
     plasticity in central neurons.

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