Abnormal Neural Processing during Emotional Salience Attribution of Affective Asymmetry in Patients with Schizophrenia

한글 요약

조현병 환자에서 정서적 현출성(salience)을 부여하는 과정의 이상이, 긍정과 부정 정서가 함께 담긴 양가적 자극을 처리할 때 어떻게 나타나는지 살핀 연구입니다. 환자와 건강한 대조군이 두 장의 그림을 나란히 보고 정서를 판단하는 과제를 fMRI 안에서 수행했으며, 정서가 비대칭인 조건(양가적·중립)과 대칭인 조건(긍정·부정)을 나누어 집단 간 비교를 했습니다. 대조군은 양가적 조건에서 내측 전전두엽과 하전두이랑의 활동이 다른 조건보다 높았지만 환자에게서는 이런 양상이 나타나지 않았고, 환자는 양가적 조건에서 배외측 전전두엽, 배측 전대상피질, 섬엽, 피각의 활동이 대조군보다 낮았습니다. 부정성 편향을 처리할 때 나타나는 다발성 전두엽 활동 저하가 정서 정보의 통합적 처리 결함을 낳고, 현출성 연결망의 이상이 조현병 증상 형성과 사회적 기능 저하에 관여할 수 있음을 시사합니다.

Aberrant emotional salience attribution has been reported to be an important clinical feature in patients with schizophrenia. Real life stimuli that incorporate both positive and negative emotional traits lead to affective asymmetry such as negativity bias and positivity offset. In this study, we investigated the neural correlates of emotional salience attribution in patients with schizophrenia when affective asymmetry was processed. Fifteen patients with schizophrenia and 14 healthy controls were scanned using functional magnetic resonance imaging (fMRI) while performing an emotion judgment task in which two pictures were juxtaposed. The task consisted of responding to affective asymmetry condition (ambivalent and neutral) and affective symmetry conditions (positive and negative), and group comparisons were performed for each condition. Significantly higher activity in the medial prefrontal cortex and inferior frontal gyrus was observed for the ambivalent condition than for the other conditions in controls, but not in patients. Compared with controls, patients showed decreased activities in the dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, insula, and putamen for the ambivalent condition, but no changes were observed for the neutral condition. Multiple prefrontal hypoactivities during salience attribution of negativity bias in schizophrenia may underlie deficits in the integrative processing of emotional information. Regional abnormalities in the salience network may be the basis of defective emotional salience attribution in schizophrenia, which is likely involved in symptom formation and social dysfunction.