Fig. 4.

Proposed integrated model of the results. (a—top) A conceptual depiction of the moderated mediation model tested. PLE and TBW were tested as serial mediators of a genetically moderated indirect link between Glx and Cognitive-Perceptual SPQ. (a—bottom) Path analysis showed that, via its genetically moderated effects on PLE and TBW, higher Glx was associated with lower SPQ in those with relatively low E/I scores (mean or lower), but with higher SPQ in those with relatively high E/I score (>1.3 SD above the mean). Notably, the mediation effect was partial, as it emerged in the context of a significant negative direct path from Glx to SPQ. Numbers represent standardized parameter estimates (bootstrapped standard errors in parentheses). Indirect (ie, serially mediated) effects are represented as parameter estimates along with 95% bias-corrected bootstrapped confidence intervals computed at representative values of the moderator (E/I genetic scores). As the model was saturated, only individual paths were tested for significance and no overall model fit statistics were produced. (b) Our results support an inverted-U shape relationship between excitation/inhibition (E/I) balance and both the temporal structure of resting state activity (Green curve) as well as the temporal resolution of multisensory perception (Red curve). Individual TBW and power spectra are depicted for subjects representative of the 4 main combinations of E/I genetic score (Purple arrows) and Glx levels (Orange arrows). Subjects for whom both are low or both are high fall on the nonoptimal left and right side of the curve, respectively, whereas those with low–high or high–low combinations are near the putative optimal level of E/I on top of the curve. TBW = temporal binding window; PLE = power law exponent; SPQ = schizotypal personality questionnaire.