Figure 7.

The four main response types. A, Phasic–tonic responses included a burst of excitation followed by tonic activity for the duration of the light flash. B, Phasic responses only involved a short response during the light flash. C, Tonic responses involved a tonic increase or decrease in the membrane potential during the light flash, which did not correlate with a significant change in spike rate. D, The on–off response type was characterized by a burst of excitation at the onset of the light flash and when the light was turned off. Calibration: 10 mV, 0.5 s (duration of the stimulus). E, The percentages of each lobula layer group exhibiting each of the response types. The majority of the tested layer 1–4 neurons (72%) exhibited a clear on–off response, whereas the majority of layer 5–6 neurons had tonic or phasic responses (72%).