Habituation of rostral anterior cingulate cortex to repeated emotionally salient pictures
ABSTRACT Habituation of the neural response to repeated stimuli has been well demonstrated for subcortical limbic regions responding to emotionally salient stimuli. Although the rostral or affective division of the anterior cingulate cortex (rACC) is also engaged during emotional processing, little is known about the temporal dynamics of this region in sustained evaluation of emotional salience. Using a test/retest design, the present study assessed habituation in the human brain with functional magnetic resonance imaging. Eight healthy subjects were exposed to two repeated runs of aversive, neutral, and blank images. Activation of the rACC to negatively valenced pictures occurred only in the first session, and this activation was significantly greater in the first relative to the second session. Additionally, medial prefrontal cortex, hippocampal, and amygdalar activations were noted during the first, but not second, presentation of aversive pictures. These findings highlight the phasic activity of the rACC in emotional processing consistent with habituation.
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ABSTRACT: Reappraisal, the cognitive reevaluation of a potentially emotionally arousing event, has been proposed to be based upon top-down appraisal systems within the prefrontal cortex (PFC). It still remains unclear, however, how different prefrontal regions interact to control and regulate emotional responses. We used fMRI and dynamic causal modeling (DCM) to characterize the functional interrelationships among dorsal and ventral PFC regions involved in reappraisal. Specifically, we examined the effective connectivity between the inferior frontal gyrus (IFG), dorsolateral PFC (DLPFC), and other reappraisal-related regions (supplementary motor area, supramarginal gyrus) during the up- and downregulation of emotions in response to highly arousing extreme sports film clips. We found DLPFC to be the central node of the prefrontal emotion regulation network, strongly interconnected with the IFG. The DCM analysis further revealed excitatory changes of connection strength from the DLPFC to the IFG and strong inhibitory changes of connection strength between the IFG and DLPFC during reappraisal. These bidirectional changes in connectivity strength indicate a feedback mechanism by which the IFG may select one out of several possible goal-appropriate reappraisals held active in working memory (represented in the DLPFC) and inhibits the DLPFC once the selection process is completed.Cerebral Cortex 01/2015; DOI:10.1093/cercor/bhv005 · 8.31 Impact Factor
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ABSTRACT: Behavioral habituation during repeated exposure to aversive stimuli is an adaptive process. However, the way in which changes in self-reported emotional experience are related to the neural mechanisms supporting habituation remains unclear. We probed these mechanisms by repeatedly presenting negative images to healthy adult participants and recording behavioral and neural responses using functional magnetic resonance imaging (fMRI). We were particularly interested in investigating patterns of activity in insula, given its significant role in affective integration, and in amygdala, given its association with appraisal of aversive stimuli and its frequent coactivation with insula. We found significant habituation behaviorally along with decreases in amygdala, occipital cortex, and ventral prefrontal cortex (PFC) activity with repeated presentation, whereas bilateral posterior insula, dorsolateral PFC, and precuneus showed increased activation. Posterior insula activation during image presentation was correlated with greater negative affect ratings for novel presentations of negative images. Further, repeated negative image presentation was associated with increased functional connectivity between left posterior insula and amygdala, and increasing insula-amygdala functional connectivity was correlated with increasing behavioral habituation. These results suggest that habituation is subserved in part by insula-amygdala connectivity and involves a change in the activity of bottom-up affective networks.Social Cognitive and Affective Neuroscience 10/2013; DOI:10.1093/scan/nst160 · 5.88 Impact Factor