The Effectiveness of Individual Synaptic Inputs with Uniform and Nonuniform Patterns of Background Synaptic Activity
The effectiveness of a synaptic input in changing the potential at the soma depends strongly on the resistance of the dendritic membrane (Barrett and Crill, 1974b; Rall, 1959), which, in turn, depends on the density and degree of opening of ionic channels in the membrane. Since ionic channels are presumed to be most highly concentrated near synapses, and since the distributions and types of synapses and their frequencies of activation may be highly nonuniform, the resistance of dendritic membrane can be expected to be nonuniform (Barrett, 1975; Eaton, 1980). Furthermore, synaptic activity, which is responsible for opening and closing ionic channels varies from moment to moment. Spatial and temporal variations in membrane resistance may cause the effectiveness of an individual synaptic input to be quite different at one moment than at another.
KeywordsSynaptic Input Reversal Potential Dendritic Segment Cortical Pyramidal Neuron Dendritic Membrane
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