Fig. 4.

Mutual information between past and future neural responses. (A) Conditional distribution $P\left(w_{t+\mathrm{\Delta }t}|w_t\right)$, at time $\mathrm{\Delta }t=1/60\hspace{0.17em}\text{s}$, for the group of four cells with the maximum information (1.1 bits/spike), in response to a natural movie. The prior distribution of words, $P\left(w\right)$, is shown adjacent to the conditional. Probabilities are plotted on a log scale; blank bins indicate zero samples. (B) Distributions of $I\left(W_t;W_{t+\mathrm{\Delta }t}\right)$ for $N=2$, $N=4$, and $N=9$ cells, with $\mathrm{\Delta }t=1/60\hspace{0.17em}\text{s}$. (C) Information between words as a function of $\mathrm{\Delta }t$. Inset shown information vs. N at $\mathrm{\Delta }t$ marked by arrows. (D) Information between words for groups of $N=9$, as a function $\mathrm{\Delta }t$ for different classes of stimuli: a natural movie, the moving bar from Fig. 1, and a random flickering checkerboard refreshed at 30 fps. Shaded regions indicate $\pm 1$ SD across different groups of cells.