自閉症成人之心智理論神經機制：社會動畫作業之功能性核磁造影研究

Abstract

心智理論(Theory of Mind, ToM)為推論他人心智狀態的能力，例如：想法、信念、慾望和意圖等，也是所有社會互動的基礎。過往研究發現自閉症患者在心智理論的能力上有所缺損，且可能為腦神經機制的異常所導致。然而，過往此類心智理論相關腦造影研究多聚焦於兒童及青少年自閉症患者，較缺乏納入自閉症成人患者作為樣本研究，樣本數較少，且目前所發現之結果也尚無定論。因此，本研究欲藉功能性磁振造影，探討健康成人與自閉症成人之心智理論神經機制。本研究共有健康組與自閉症組成人各24位，使其於掃描時進行心智理論作業-社會動畫作業。作業中會出現兩個三角形，受試者需判斷兩者是否正進行互動，抑或隨機移動。結果發現，自閉症組較健康組於左側楔前葉腦區(precuneus)、右上側顳腦迴(superior temporal gyrus, STG)、及右中側額葉迴(middle frontal gyrus, MFG)有較高活化量，而健康組較自閉症組於左側中央前迴(precentral gyrus)、及右側腦島區(insula)有較低活化量。結果亦顯示自閉症組較高的右上側顳腦迴活化，與其日常社會溝通行為上的缺損有顯著關聯。綜上所述，本研究認為自閉症成人與正常健康發展成人之心智理論神經機制有所不同，且自閉症成人患者於心智理論神經機制上的缺損，亦干擾其日常社交互動之功能。

Theory of Mind (ToM), defined as the ability to infer another person's mental states, such as beliefs, desires, and intentions, is a fundamental process of social interaction. The deficit of ToM is one of the core features of autism spectrum disorder (ASD). The present study aimed to explore the differential neural substrates of ToM using the social animation task (Castelli et al., 2000) between ASD adults and healthy controls. We assessed 24 healthy controls (mean age: 20.99±2.03) and 24 adults with ASD (mean age: 22.10±1.93) with the social animation task of ToM, which featured two triangles moving on a framed background with ToM and control animations. Participants were asked to decide if a social interaction was presented for each animation in functional MRI. The imaging analyses were conducted to explore the process of ToM. Correlation analysis were conducted to explore the relationship between neural activations associated with ToM and social interaction abilities measure by the Social responsiveness scale (SRS) and the Chinese version of Autism Diagnostic Interview, Revised (ADI-R). In within-group contrast, the [ToM-Random] exhibited common activation in the bilateral superior temporal gyri (STG), right middle temporal gyri (MTG), and left inferior frontal gyrus (IFG) across two groups. In between-groups contrast, the [ToM-Random] displayed greater activation in the left precuneus, right superior temporal gyrus (STG), right middle frontal gyrus (MFG) in ASD than the controls. Reversed comparisons showed that the controls displayed additional activation in left precentral gyrus and right insula relative to the ASD group. For correlation analysis, greater right superior temporal gyrus(STG) activation was positively correlated with the ADIR Qualitative Communication Abnormalities in the ASD group. Aberrant neural activities of ToM in ASD suggest that adults with ASD might spend a great deal of effort on ToM processing. The correlation finding implied that adults with ASD might spend excessive effort on the identification processing, thereby influencing the performance of social communication skills. In summary, the results indicated that the neural deficits of ToM in ASD might be associated with their daily social interaction difficulties.