Coding of Dynamic Stimuli: Spike Timing, Number, and Pattern

Pamela Reinagel

Department of Neurobiology

Harvard Medical School

When an animal is presented with a time-varying visual stimulus, the responses of visual neurons can be highly reliable given the same stimulus, the trial-to-trial variation in response is surprisingly small. I will discuss three aspects of response reliability in the LGN (lateral geniculate nucleus). First, the timing of spikes can be reliable to a millisecond; in other words, the probability of firing can be modulated with msec precision. Second, the number of spikes in any epoch of the response is reliable from trial to trial (variance in spike count is much less than mean count). Third, local temporal patterns of spikes are sometimes even more reliable than implied by the first two points. I will discuss the extent to which each of these contributes to the overall information content of the neural response, and speculate about how these response properties arise, and whether the encoded information could be read out by downstream cortical neurons.