Bistable behaviour in a neocortical neurone model

INTRACELLULAR recordings have shown that neocortical pyramidal neurones have an intrinsic capacity for regenerative firing. The cellular mechanism of this firing was investigated by computer simulations of a model neurone endowed with standard action potential and persistent sodium (g(NaP)) conductances. The firing mode of the neurone was determined 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 activity (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 maintenance of long-lasting sustained neuronal discharges in the cerebral cortex.