Öjvind Bernander, Christof Koch, Rodney Douglas
Intradendritic electrophysiological recordings reveal a bewildering repertoire of complex electrical spikes and plateaus that are dif(cid:173) ficult to reconcile with conventional notions of neuronal function. In this paper we argue that such dendritic events are just an exu(cid:173) berant expression of a more important mechanism - a proportional current amplifier whose primary task is to offset electrotonic losses. Using the example of functionally important synaptic inputs to the superficial layers of an anatomically and electrophysiologically re(cid:173) constructed layer 5 pyramidal neuron, we derive and simulate the properties of conductances that linearize and amplify distal synap(cid:173) tic input current in a graded manner. The amplification depends on a potassium conductance in the apical tuft and calcium conduc(cid:173) tances in the apical trunk.
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