How the shape of pre- and postsynaptic signals can influence STDP: a biophysical model.
Spike-timing-dependent plasticity (STDP) is described by long-term potentiation (LTP), when a presynaptic event precedes a postsynaptic event, and by long-term depression (LTD), when the temporal order is reversed. In this article, we present a biophysical model of STDP based on a differential Hebbian learning rule (ISO learning). This rule correlates presynaptically the NMDA channel conductance with the derivative of the membrane potential at the synapse as the postsynaptic signal. The model is able to reproduce the generic STDP weight change characteristic. We find that (1) The actual shape of the weight change curve strongly depends on the NMDA channel characteristics and on the shape of the membrane potential at the synapse. (2) The typical antisymmetrical STDP curve (LTD and LTP) can become similar to a standard Hebbian characteristic (LTP only) without having to change the learning rule. This occurs if the membrane depolarization has a shallow onset and is long lasting. (3) It is known that the membrane potential varies along the dendrite as a result of the active or passive backpropagation of somatic spikes or because of local dendritic processes. As a consequence, our model predicts that learning properties will be different at different locations on the dendritic tree. In conclusion, such site-specific synaptic plasticity would provide a neuron with powerful learning capabilities.
Saudargiene
Ausra
A
Department of Psychology, University of Stirling, Stirling FK9 4LA, Scotland, U.K. ausra@cn.stir.ac.uk
Porr
Bernd
B
Wörgötter
Florentin
F
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006801:Humans; D007858:Learning / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008959:Models, Neurological; D016202:N-Methylaspartate / Q000494:pharmacology; D009431:Neural Conduction / Q000187:drug effects / Q000528:radiation effects; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D013569:Synapses / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D009435:Synaptic Transmission / Q000187:drug effects / Q000528:radiation effects; D013997:Time Factors; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid