Figure 12.

Facilitation by V2 stimulation is more effective for small WM responses. (A) Fluorescence traces recorded from 4 representative cells simultaneously in Au1 in response to WM (first and third columns), paired V2L–WM (second and fourth columns) stimulation for 2 different WM stimulation intensities: 75 μA (first and second columns) and 100 μA (third and fourth columns). V2L stimulation intensity was identical in both cases (200 μA). Four pulses each were applied to WM and V2L, at 0 ms delay. Note that for the lower WM stimulation intensity, all 4 cells exhibit facilitation in response to paired stimulation, but for the higher WM stimulation intensity, this is true only for cells 1 and 2. (B) Summary of all recordings from the experiment in (A) (mean ± standard error of the mean; n = 30 cells) showing the difference between response amplitude (%ΔF/F) to paired stimulation versus WM alone. Note greater facilitation (i.e., greater difference) for smaller WM stimulation intensity.