Figure 7.

In contrast to the simple FRB cells, the complex FRB cells did not show stimulus-dependent γ oscillations. A, Complex FRB cell stimulated with an optimal drifting sinusoidal grating (top). After spike removal, the trace was filtered between 10 and 100 Hz (middle trace) and between 30 and 50 Hz (bottom trace). During the visual stimulation, the cell showed a DC depolarization and large deflections at ∼20 Hz but very little γ activity (details 1 and 2). B, Like the simple cell, this cell responded to a depolarizing current pulse of 0.9 nA with the typical FRB bursting pattern. C, The interspike interval histogram of visually (Vis.) evoked activity showed a peak at short latencies but no peak at 25 ms. D, The normalized (Norm.) mean power spectrum (400 ms; n = 8) during stimulation with the optimally oriented grating (black line) showed only a very small increase in power between 30 and 50 Hz compared with the response to the nonoptimal grating (18° from optimal) (gray line).