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Presenter: Estibaliz Arce, Ph.D., University of California, San Diego
Discussant / Mentor: Pedro Delgado, M.D., University of Texas, Health and Sciences, San Antonio

Brain activation differences between Latino and Caucasian women suffering from post-traumatic stress disorder: A neural basis for differential processing of emotion?

Authors: Estibaliz Arce, Murray B. Stein, Martin P. Paulus

Background:
Emotion is used as a generic umbrella term that includes specific constellations of arousal, valence, and qualitatively differentiated body states.  An emerging body of literature supports the notion that emotion processing is strongly influenced by culture. For example, higher rates of somatic concerns have been reported among Latinos as compared to Euro-Americans and African Americans.  Interoception can be defined as the sense of the physiological condition of the entire body (Craig 2002).  Interoception is critical for self-awareness because it provides the link between cognitive/affective processes and current body state.  The insular cortex is part of a neural system important for the processing and integration of interoceptive information.  The aim of this study was to determine whether Latinos and Euro-Americans suffering from post-traumatic stress disorder (PTSD) process emotions differently.  Specifically, it was hypothesized that, if Latino women have a stronger representation of somatic states associated with emotion processing, they would show increased activation in the interoceptive neural system.

Methods:
Six American women from European descent were compared with 5 age- and education-matched Latin American descent women. Individuals from both groups were diagnosed with PTSD as a result of traumatic experiences in the context of domestic violence. All subjects underwent functional magnetic resonance imaging (fMRI) while performing an emotional anticipation task.

Results:
Relative to Euro-American, Latino women with PTSD exhibited relatively more activation in bilateral insular, bilateral anterior cingulate cortex and right amygdala while anticipating emotionally aversive images.

Conclusions:
Our preliminary results are consistent with the hypothesis that increased somatic representation of emotion in Latino women is associated with increased activation of the interoceptive neural system. Specifically, the insular cortex was more active in the Latino group, which may indicate that the representation of emotion in this group is more strongly based on integration of interoceptive body
states than that of Euro-American women. These findings, if replicated with larger samples, could
have important implications for the assessment and treatment of emotion disorders in Latino individuals.