Figure 1.

Tracking and Non-tracking Units in the AC of C. perspicillata

(A and B) Peri-stimulus time histograms (1-ms bins) of a cortical tracker (A) and a non-tracker (B).

(C) Vector strength (VS) of the tracking unit depicted in (A), for all modulation frequencies tested. This unit was significantly synchronized (according to the joint criterion, see Transparent Methods) to modulation frequencies up to 8.57 Hz (red stars).

(D) VS of the non-tracking unit shown in (B). Solid black lines in (C and D) represent the median VS across trials; gray-shaded areas illustrate the interquartile range (IQR). Waveforms on top of VS curves represent the spike shape of each unit (C, tracker, n = 3,715 spikes; D, non-tracker, n = 1,074 spikes; all spikes are included to obtain the waveform).

(E) Vector strength of tracking (blue circles) and non-tracking (red squares) units; solid lines show median values, whereas shaded areas indicate the IQR. (* symbols indicate the results of FDR-corrected Wilcoxon rank-sum tests; **p < 0.01, ***p < 0.001).

(F) Distribution of cutoff frequencies in the population of trackers (black bars; non-trackers represented by the gray bar). The gray arrow indicates a cutoff frequency of 22.63 Hz.