Poster B18, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
STRESS-MEDIATED ALTERATIONS OF AMYGDALAR ACTIVATION AND CORTICAL NETWORK COHERENCE ASSOCIATED WITH SEROTONIN TRANSPORTER POLYMORPHISMS
David Beversdorf1, Neetu Nair1, John Hegarty1,2, Katherine Lane1, Bradley Ferguson1, Patrick Hecht1, Michael Tilley3, Jeffrey Johnson1, Shawn Christ1; 1University of Missouri, 2Stanford University, 3Central Methodist University
Impaired cognitive processing is associated with disrupted coherence within neuronal networks, and stress can impair cognitive performance. We previously found greater cognitive impairment due to stress in subjects with at least one copy of the short (S) allele (lacking a 44bp repeat in the promoter region as compared to the long (L) allele) of the serotonin transporter gene (SERT), which results in lower SERT expression with those with the S/S or S/L genotype than those with L/L genotype. Altered amygdalar activity is also associated with this SERT-associated variability in stress response. To determine whether stress-susceptibility affects coherence in response to stress, and how amygdalar reactivity relates, graph metrics were collected with fMRI during the resting state in 35 subjects (17 with S-allele). Subjects attended counterbalanced sessions exposed to the Montreal Imaging Stress Task (MIST), or the non-stressful controlMIST condition. ROIs were assessed for global connectivity patterns. During subsequent MIST resting phases, the subject was interrupted exposure to angry/fearful or neutral expression faces for amygdalar activation, alternating with MIST/controlMIST epochs. ANOVA revealed a gene x stress condition interaction for functional clustering of neighboring nodes with among graph metrics (p=0.039), with the significant alteration in clustering driven by those with the S-allele (p=0.016). Stress induced resting-state connectivity changes in the same gene-dependent manner as previously demonstrated for effects on cognitive performance. Ongoing mediation analysis is revealing how amygdala reactivity relates to this effect. Future research will be needed to further understand the mechanism by which stress impairs performance on cognitive flexibility tasks.
Topic Area: EMOTION & SOCIAL: Emotion-cognition interactions