The role of spike timing in the coding of stimulus location in rat somatosensory cortex

Although the timing of single spikes is known to code for time-varying feat ures of a sensory stimulus, it remains unclear whether time is also exploit ed in the neuronal coding of the spatial structure of the environment, wher e nontemporal stimulus features are fundamental. This report demonstrates t hat, in the whisker representation of rat cortex, precise spike timing of s ingle neurons increases the information transmitted about stimulus location by 44%, compared to that transmitted only by the total number of spikes. C rucial to this code is the timing of the first spike after whisker movement . Complex, single neuron spike patterns play a smaller, synergistic role. T iming permits very few spikes to transmit high quantities of information ab out a behaviorally significant, spatial stimulus.