Efficient discrimination of temporal patterns by motion-sensitive neurons in primate visual cortex

Giedrius T Buracas, Anthony M Zador, Michael R DeWeese, Thomas D Albright

Abstract: Although motion-sensitive neurons in macaque middle temporal (MT) area are conventionally characterized using stimuli whose velocity remains constant for 1–3 s, many ecologically relevant stimuli change on a shorter time scale (30–300 ms). We compared neuronal responses to conventional (constant-velocity) and time-varying stimuli in alert primates. The responses to both stimulus ensembles were well described as rate-modulated Poisson processes but with very high precision (∼3 ms) modulation functions underlying the time-varying responses. Information-theoretic analysis revealed that the responses encoded only ∼1 bit/s about constant-velocity stimuli but up to 29 bits/s about the time-varying stimuli. Analysis of local field potentials revealed that part of the residual response variability arose from “noise” sources extrinsic to the neuron.