INDIVIDUAL DIFFERENCES IN EMOTIONAL JUDGMENTS OF SOUNDS ARE ASSOCIATED WITH ANXIETY AND THALAMO-AMYGDALA WHITE MATTER CONNECTIVITY

Classic models of emotion suggest that detection of affective signals depends on anxiety and relies on direct thalamo-amygdala connectivity. However, whether these mechanisms predict subjective emotion judgments remains unclear. We investigated whether subjective emotional ratings of sounds relate to individual anxiety levels and thalamo-amygdala white matter structural connectivity. Sixty healthy young participants rated 300 naturalistic sounds along multiple affective dimensions. We derived measures of perceptual bias, rating consistency (spread), and negative-positive discrimination (contrast index). Anxiety was assessed using the State-Trait Anxiety Inventory. In a subsample of participants (n = 19), diffusion imaging tractography was used to characterize connections from specific posterior thalamic nuclei to the basolateral amygdala (BLA), using both streamline and fixel-based analyses. Finally, we tested linear associations between individual affective ratings, anxiety scores, and structural connectivity of these pathways.
Higher state anxiety was associated with reduced rating variability for emotionally negative stimuli, as well as with increased judgments of neutral sounds as more negative, consistent with negatively biased emotional evaluations. In turn, increased structural connectivity of an auditory medial geniculate body-BLA pathway was linearly associated with a negative perceptual bias and with enhanced discrimination between negative and positive sounds. In contrast, increased connectivity of medial and inferior pulvinar-BLA pathways was associated with perceptual bias toward neutral and positive emotion. All connectivity associations were independent of individual anxiety levels. Together, these findings indicate that anxiety and thalamo-amygdala connectivity make dissociable contributions to subjective emotional perception, and suggest pathway-specific roles in auditory emotional evaluation.