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Dynamic synapses as archives of synaptic history: state‐dependent redistribution of synaptic efficacy in the rat hippocampal CA1
Author(s) -
Yasui Takuya,
Fujisawa Shigeyoshi,
Tsukamoto Masako,
Matsuki Norio,
Ikegaya Yuji
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.086595
Subject(s) - synaptic plasticity , synaptic augmentation , neuroscience , long term potentiation , metaplasticity , synaptic fatigue , neuronal memory allocation , nonsynaptic plasticity , synapse , synaptic scaling , long term depression , biology , neurotransmission , homosynaptic plasticity , excitatory postsynaptic potential , ampa receptor , inhibitory postsynaptic potential , glutamate receptor , receptor , biochemistry
Plastic modifications of synaptic strength are putative mechanisms underlying information processing in the brain, including memory storage, signal integration and filtering. Here we describe a dynamic interplay between short‐term and long‐term synaptic plasticity. At rat hippocampal CA1 synapses, induction of both long‐term potentiation (LTP) and depression (LTD) was accompanied by changes in the profile of short‐term plasticity, termed redistribution of synaptic efficacy (RSE). RSE was presynaptically expressed and associated in part with a persistent alteration in hyperpolarization‐activated I h channel activity. Already potentiated synapses were still capable of showing RSE in response to additional LTP‐triggering stimulation. Strikingly, RSE took place even after reversal of LTP or LTD, that is, the same synapse can display different levels of short‐term plasticity without changing synaptic efficacy for the initial spike in burst presynaptic firing, thereby modulating spike transmission in a firing rate‐dependent manner. Thus, the history of long‐term synaptic plasticity is registered in the form of short‐term plasticity, and RSE extends the information storage capacity of a synapse and adds another dimension of functional complexity to neuronal operations.