BISTABLE BEHAVIOR IN A NEOCORTICAL NEURON MODEL

INTRACELLULAR recordings have shown that neocortical pyramidal neurone s have an intrinsic capacity for regenerative firing. The cellular mec hanism of this firing was investigated by computer simulations of a mo del neurone endowed with standard action potential and persistent sodi um (g(NaP)) conductances. The firing mode of the neurone was determine d as a function of leakage and NaP maximal conductances ((g) over bar( l) and (g) over bar(NaP)). The neurone had two stable states of activi ty (bistable) over wide range of (g) over bar(l) and (g) over bar(NaP) , one at the resting potential and the other in a regenerative firing mode, that could be triggered by a transient input. This model points to a cellular mechanism that may contribute to the generation and main tenance of long-lasting sustained neuronal discharges in the cerebral cortex.