Figure 2

Social Investigation-Elicited Gamma Power Is Impaired in SRKO mice. Frontal cortex social investigation-elicited gamma power (25–58 Hz) was recorded during the behavioral task described in Fig. 1. Grand average spectrograms appear in (A,B) and (D,E) (% of baseline power), while the investigation-elicited gamma power normalized to background gamma is graphed in (C) and (F). The dotted line represents the start of the novel mouse investigation (time 0) and the white boxes outline the data that was analyzed in 0.5 s bins. WT mice (n = 8) had a significantly larger increase in gamma power than SRKO animals (n = 5) during 0.5–1 s for the sociability task (C), and 0–1 s for the social novelty task (F). Greater background gamma power (0–4 s prior to novel mouse investigation, percent of total power) was evident in SRKO mice compared to WT littermates during the social novelty task (H) but not the sociability task (G), suggesting an improper signal-to-noise ratio may contribute to the difference in elicited gamma. Furthermore, there were significant inverse correlations such that greater background gamma power was associated with reduced investigation-elicited gamma power for all novel mouse investigations across both trials for WT (I, n = 232 investigations) and SRKO (J, n = 127 investigations) animals. In the repeated measures correlations, each dot represents a single investigation of a novel mouse, and each individual mouse is represented by a unique color. The data in Fig. 1 and 2 suggest SRKO mice have a deficit in social-elicited gamma in response to a novel mouse investigation. Enhanced background gamma in SRKO mice may be a contributing factor to this deficit. Stars represent significance from multiple t-tests with Holm–Sidak correction (C,F) or a Mann–Whitney U test (H).