Amygdala habituation and uncinate fasciculus connectivity in adolescence: A multi-modal approach

Abstract

Despite prior extensive investigations of the interactions between the amygdala and prefrontal cortex, few studies have simultaneously considered activation and structural connectivity in this circuit, particularly as it pertains to adolescent socioemotional development. The current multi-modal study delineated the correspondence between uncinate fasciculus (UF) connectivity and amygdala habituation in a large adolescent sample that was drawn from a population-based sample. We then examined the influence of demographic variables (age, gender, and pubertal status) on the relation between UF connectivity and amygdala habituation. 106 participants (15-17 years) completed DTI and an fMRI emotional face processing task. Left UF fractional anisotropy was associated with left amygdala habituation to fearful faces, suggesting that increased structural connectivity of the UF may facilitate amygdala regulation. Pubertal status moderated this structure-function relation, such that the association was stronger in those who were less mature. Therefore, UF connectivity may be particularly important for emotion regulation during early puberty. This study is the first to link structural and functional limbic circuitry in a large adolescent sample with substantial representation of ethnic minority participants, providing a more comprehensive understanding of socioemotional development in an understudied population.

Keywords: Adolescence; Amygdala; DTI; Emotion; fMRI.

Figure 1.

There was a positive relation between left UF FA and left amygdala habituation to fearful faces, t (96) = 3.76, p = .003, XYZ = −26, −2, −18. Left UF FA estimates were extracted from a structural left UF ROI and entered as regressors in a multiple regression analysis in SPM8. Note: we would like figure 1 to be in color.

Figure 2.

In a confirmatory analysis in RStudio, Left amygdala habituation to fearful faces is positively correlated with mean FA values extracted from the left UF, r = 0.314, p = 0.002. Left amygdala habituation parameter estimates were extracted from a structural left amygdala ROI from WFU PickAtlas, and left UF FA estimates were extracted from a structural left UF ROI.

Figure 3.

The association between left UF FA and left amygdala habituation to fearful faces is moderated by puberty, B = −15.340, SE = 6.464, t (95) = −2.373, p = 0.0197, such that left UF FA was more predictive of left amygdala habituation to fearful faces in participants who were earlier in pubertal development relative to participants who were later in pubertal development. The coloring in the figure represents pubertal status; the dotted green line and green shading represents participants who are later in pubertal development (at the mean plus the standard deviation of pubertal development for this sample or greater), the dashed red line and red shading represents participants who are average in their pubertal development, and the black solid line and black shading represent participants who are earlier in pubertal development (at the mean minus the standard deviation of pubertal development for this sample or less). Note: we would like figure 3 to be in color.