Supralinear summation of synaptic inputs in the leech AP neuron: dendritic gain Is mediated by an 'inward Rectifier' K+ current

摘要

We focus on the sumation of sensory input by a projection neuron, the Anterior Pagoda (AP) cell, of leech. This cell receives monsynaptic glutamatergic input from 4 identified pressure sensitive (P) sensory cells that may be stimulatd individually or simultaneously in the isolated, intact ganglion. We observe, starting at potentials just below the AP cell spike-threshold (-55 mV), that the amplitude of individual excitatory postsynaptic potentials (EPSPs) decreases with hyperpolarization. Further, the a;litude of the EPSP observed in response to the simultaneous activation of a pair of P cells is up to 50