Figure 3.

Gamma-band activity during repetition of natural stimuli

(A) LFP power spectra, averaged over all sites and sessions of monkey K, for two example stimuli. Colored lines correspond to the indicated repetition numbers. Shaded areas indicate ±1 SEM across 11 sessions.

(B) Repetition-related change for early, late, or all repetitions (see STAR Methods).

(C) Black line: grand average gamma-band LFP power as a function of stimulus repetition number. Green line: same analysis after removing all immediate repetitions of a given stimulus. Vertical line separates “early” from “late” repetitions. Inset: average linear slopes of fits to the early and late repetitions, respectively.

(D) Same as black line in (C), with separate lines per stimulus and animal (line colors approximate stimulus color).

(E) Scatterplot of repetition-related gamma-power change (slope) as a function of gamma-response strength (intercept), for one example animal. Each circle reflects a stimulus-site combination. Bar plots: Spearman correlation coefficient between slopes and intercepts averaged over animals, for fits to all, early, and late trials, respectively. Error regions show ±2 SEM (bootstrap, see STAR Methods), for illustration, whereas statistical inferences were based on non-parametric permutation tests, including correction for multiple comparison if necessary.

(F–H) Scatterplots of linear slopes of late versus early trials (see STAR Methods). Each color-symbol combination corresponds to the combination of a stimulus and an animal. Note different axes scales; dashed line is the equality line. (F) Gamma-band LFP power; colored lines: significant linear fits per animal. R and p values give average over monkeys. (G and H) dMUA responses for 0.5–1.5 s (G) or 0.05–0.15 s (H) post-stimulus onset. For dMUA, no significant relations were observed.