Fig. 5. The influence of handedness and gender on the occurrence rates of lateralized brain states.

(A) The occurrence rate of lateralized brain states was computed in 52 left-handed and 52 demographically matched right-handed subjects. Right-handed subjects showed a significantly higher occurrence rate in right-lateralized state 11 relative to left-handers (two-sample t test, *P = 0.044). The occurrence rate distributions for lateralized states 15 and 11 are displayed in the histograms with left-handed subjects depicted by blue bars and right-handed subjects denoted by pink bars, with the overlap of the two shown in purple. The distributions were fitted using Gaussian curves and demonstrate that right-handed subjects showed a higher occurrence rate in state 11 than left-handed subjects (Kolmogorov-Smirnov test, P = 0.021). (B) Occurrence rate of lateralized brain states 15 and 11 across 279 males and 279 matched females. Bar graph depicts the mean percentage of occurrence (±SEM) of states 15 and 11 in male (yellow bars) and female (green bars) subjects. Males demonstrated a significantly higher occurrence of state 11 (two-sample t test, **P = 0.008) and a trend toward a higher occurrence rate in state 15 that approached significance (paired t test, P = 0.054) compared to females. The occurrence rate distributions for these two states are graphically displayed and demonstrate that males (yellow bars) showed a significantly higher occurrence rate in right-lateralized state 11 than females (green bars) (Kolmogorov-Smirnov test, P = 0.017).