Induced and evoked γ responses during vocalization. A, B, Two example recording sites are shown, demonstrating two components of the γ-band response. Top, Time-frequency plots. Middle, MUA responses. Bottom, γ power. Both total (black) and nonsynchronized γ power (induced; blue) are plotted. Error bars indicate SEM. Significant changes in total γ are indicated (green; p < 0.05), as are time bins with significant differences between total and induced γ (red). C, Population histogram of total γ responses during vocalization showing large increases in vocal γ power. Sites with significant γ responses (p < 0.05) are filled, and accounted for 42% of all recorded sites. Mean and SD of the distribution are indicated, as is the number of significant sites (# sig). D, Distribution of vocal γ power divided into induced (blue) and evoked (red) responses. Filled bins represent sites with significant responses, as above. E, Distribution of peak response times, relative to vocal onset, for sites with significant evoked (left) and induced (blue) vocal γ responses. Evoked activity peaked early after vocal onset, with induced activity peaking later. F, Histogram of evoked and induced γ power immediately after vocal onset (averaged over 0-50 ms), showing larger evoked responses. G, Scatter plot comparing onset-evoked responses and sustained induced responses across the population. Colored markers represent sites with significant responses (p < 0.05): red represents evoked; blue represents induced; purple represents both. H, Histograms of vocal oscillatory power in other frequency bands: theta (4–8Hz), alpha (8–12 Hz), beta (12–25 Hz), and high γ (70–150 Hz). Reduced power was noted in alpha and high γ but not theta or beta-bands.