Fig 2. Fano factors differ significantly between MT responses recorded in alert versus anesthetized primates.

(A) The relationship between spike count and spike count variance in alert (blue circles) and anesthetized (orange circles) experiments. Each circle indicates a single neuron under a single stimulus condition. Histogram above shows distribution of spike counts observed in both experiments. The histogram to the right shows the distribution spike count variance values in both experiments. Stimulus directions shown are within 45° of the preferred motion direction, in 15° increments. (B) Distribution of spike count Fano factors for alert (blue) and anesthetized (orange) experiments. Solid trace indicates the best-fit lognormal distribution for each case. (C) Distribution of Fano factors as a function of spike count for alert experiments (blue) and anesthetized experiments (orange). Black circles and triangles indicate the median Fano factor binned by spike count in alert and anesthetized experiments, respectively. Error bars show the standard deviation of Fano factors in each bin. The solid and dashed traces are the linear best fit for alert and anesthetized states, respectively (r² = 0.05 alert, r² = 0.02 anesthetized).