Figure 4.
Mediation Models for BDNF and HVA. Mediation model for BDNF (A) along with corresponding histogram of bootstrapped indirect effects and 95% CI (B) indicated that circulating concentrations of BDNF mediated the relationship between aerobic exercise and reduced threat expectancy ratings following reinstatement. Mediation model for HVA (C), along with corresponding histogram of bootstrapped indirect effects and 95% CI (D) indicated that circulating concentrations of HVA did not mediate the relationship between aerobic exercise and reduced threat expectancy ratings following reinstatement. Values listed are standardized regression coefficients for path a (effect of independent variable on biomarker variable), path b (effect of biomarker variable on dependent variable), the indirect effect (product of regression coefficients for predictor variables in path a and b), path c (effect of independent variable on dependent variable without biomarker variable included in model), and path c’ (difference between direct and indirect effect). 95% CI for the indirect effect (used to determine if mediation occurred; denoted * for 95% CIs not containing zero) was obtained from bootstrap procedure involving resampling with replacement and 10,000 iterations.