Spike timing-dependent plasticity: a learning rule for dendritic integration in rat CA1 pyramidal neurons
Résumé
Long-term plasticity of dendritic integration is induced in parallel with long-term potentiation (LTP) or depression (LTD) based on presynaptic activity patterns. It is, however, not clear whether synaptic plasticity induced by temporal pairing of pre-and postsynaptic activity is also associated with synergistic modification in dendritic integration. We show here that the spike timing-dependent plasticity (STDP) rule accounts for long-term changes in dendritic integration in CA1 pyramidal neurons in vitro. Positively correlated pre-and postsynaptic activity (delay: +5/+50 ms) induced LTP and facilitated dendritic integration. Negatively correlated activity (delay: −5/−50 ms) induced LTD and depressed dendritic integration. These changes were not observed following positive or negative pairing with long delays (> ±50 ms) or when NMDA receptors were blocked. The amplitude–slope relation of the EPSP was facilitated after LTP and depressed after LTD. These effects could be mimicked by voltage-gated channel blockers, suggesting that the induced changes in EPSP waveform involve the regulation of voltage-gated channel activity. Importantly, amplitude–slope changes induced by STDP were found to be input specific, indicating that the underlying changes in excitability are restricted to a limited portion of the dendrites. We conclude that STDP is a common learning rule for long-term plasticity of both synaptic transmission and dendritic integration, thus constituting a form of functional redundancy that insures significant changes in the neuronal output when synaptic plasticity is induced.
Domaines
Neurobiologie
Origine : Publication financée par une institution
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