Figure 8.

Split-field noise stimuli cause positive correlations between excitatory and inhibitory inputs to parasol cells. A, Conductances and firing rate in response to a random split-field stimulus. Changes in light intensity on one half of the split field were matched by equal and opposite changes on the other half. B, Cross-correlation function for mean excitatory and inhibitory conductances as in A. The main panel shows mean ± SEM for 5 cells, and the inset shows the cell from A. Calibration: Inset, 50 ms, correlation 0.2. C, Cross-correlation of pre-spike conductances, mean ± SEM for 4 cells. Inset shows trajectories of excitatory (blue) and inhibitory (red) conductances before a spike. Calibration: 1 nS, 50 ms.