title: Biophysical model of a Hebbian synapse.
abstract: We present a biophysical model of electrical and Ca(2+) dynamics following activation of N-methyl-D-aspartate (NMDA) receptors located on a dendritic spine. The model accounts for much of the phenomenology of the induction of long-term potentiation at a Hebbian synapse in hippocampal region CA1. Computer simulations suggested four important functions of spines in this Ca(2+)-dependent synaptic modification: (i) compartmentalizing transient changes in [Ca(2+)] to just those synapses that satisfy the conjunctive requirement for synaptic modification; (ii) isolating the spine head from changes in the [Ca(2+)] at the dendritic shaft; (iii) amplifying the concentration changes at those synapses; and (iv) increasing the voltage dependence of the processes underlying long term potentiation induction. This proposed role of spines in the regulation of Ca(2+) dynamics contrasts with traditional approaches to spine function that have stressed electronic properties. This model can be used to explore the computational implications of Hebbian synapses.
authors.affiliation: Department of Psychology, Yale University, New Haven, CT.
authors.forename: A
authors.initials: A
authors.lastname: Zador
authors.forename: C
authors.initials: C
authors.lastname: Koch
authors.forename: T H
authors.initials: TH
authors.lastname: Brown
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism; D008959:Models, Neurological; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000502:physiology; D013131:Spine / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D002118:Calcium