Amygdala Cortical and Subcortical Pathology in Unipolar Depression: Examining Age and Sustained Emotion-Linked Physiological Responses

Abstract

The amygdala plays a crucial role in processing emotionally significant stimuli, relaying neural messages to higher cortical regions. Emotional reactivity, especially to negative events, has been known to engage limbic system structures, driving sympathetic nervous system responses. Direct correlations between structural and functional amygdala irregularities have been linked to increased vulnerability to depression. In addition, facial-emotion stimuli have been known to engage amygdala activity. This study engages in the variability of skin conductance in relation to depressive symptoms and age. Eighteen participants were divided into four distinct groups (depressive young adults, healthy young adults, depressive adults, and healthy adults). Participants viewed emotionally evoking facial-emotion stimuli in a block design while skin conductance was recorded. Group differences in SCR were analyzed to explore psychophysiological indicators of sustained depressive emotions across age groups. Although no significant difference between groups was found, the potential for age-dependent variability and the application of skin conductance in depression research could provide a non-invasive measurement of depressive symptoms. This study references my previous work (Fairback, 2024).