BDNF and Anxiety: Correlational analyses across all ages and genotypes related both amygdala BDNF and NR1 levels to basal anxiety, with lower expression levels following testing being related to higher freezing during the habituation period (BDNF: r(43) = 0.307, p = 0.045; NR1: r(46) = 0.310, p = 0.036) (Figure S3).