Figure 2.

Low-beta coherence is modulated by stimulus category. Modulation of FFC was assessed for (A) Cat versus Dog categories and (B) Goc versus Tad categories. Evidence for FFC modulation was quantified by measuring the absolute difference in coherence (|ΔFFC|) and normalizing this quantity by its trial-shuffled null distribution. The resulting z-score has an expected value of 1 under the null hypothesis (no sensitivity). Spectrograms show average z-scores of |ΔFFC| for all electrode pairs across time and frequency. Histograms show distributions of these z-scored |ΔFFC| values, and also of raw coherence differences (ΔFFC), at 18 Hz for both sample and delay stages. Electrode pairs with significant category selectivity (Sig.) were identified by permutation test. C, cue; F, fixation; S, sample; D, delay.