RELIABILITY OF SPIKE TIMING IN NEOCORTICAL NEURONS

It is not known whether the variability of neural activity in the cere bral cortex carries information or reflects noisy underlying mechanism s. In an examination of the reliability of spike generation using reco rdings from neurons in rat neocortical slices, the precision of spike timing was found to depend on stimulus transients. Constant stimuli le d to imprecise spike trains, whereas stimuli with fluctuations resembl ing synaptic activity produced spike trains with timing reproducible t o less than 1 millisecond. These data suggest a low intrinsic noise le vel in spike generation, which could allow cortical neurons to accurat ely transform synaptic input into spike sequences, supporting a possib le role for spike timing in the processing of cortical information by the neocortex.