Flip side of synaptic plasticity: Long-term depression mechanisms in the hippocampus

Authors

  • Brian R. Christie,

    1. Department of Psychology and the Neuroscience Research Centre, University of Otago, Dunedin, New Zealand
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  • D. Steven Kerr,

    1. Department of Psychology and the Neuroscience Research Centre, University of Otago, Dunedin, New Zealand
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  • Dr. Wickliffe C. Abraham

    Corresponding author
    1. Department of Psychology and the Neuroscience Research Centre, University of Otago, Dunedin, New Zealand
    • Department of Psychology, University of Otago, P.O. Box 56, Dunedin, New Zealand
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Abstract

There is growing interest in the phenomenon of long-term depression (LTD) of synaptic efficacy that, together with long-term potentiation (LTP), is a putative information storage mechanism in mammalian brain. In neural network models, multiple learning rules have been used for LTD induction. Similarly, in neurophysiological studies of hippocampal synaptic plasticity, a variety of activity patterns have been effective at inducing LTD, although experimental paradigms are still being optimized. In this review the authors summarize the major experimental paradigms and compare what is known about the mechanisms of LTD induction. Although all paradigms appear to initiate a cascade of events leading to an elevated level of Ca2+ postsynaptically, the extent to which these paradigms involve common expression mechanisms has not yet been tested. The authors discuss several critical experiments that would address this latter issue. Numerous questions about the properties and mechanisms of LTD(s) in the hippocampus remain to be answered, but it is clear that LTD has finally arrived, and will soon be attracting attention equal to its flip side, LTP. © 1994 Wiley-Liss, Inc.

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