成人注意力不足過動症患者與正常人進行決策評價的神經歷程差異

Abstract

背景：成人過動症傾向在決策評價的歷程中會有較為冒險的行為。此研究的目的為評估過動症的冒險行為是否與前額葉、紋狀體以及內側顳葉等的神經迴路對於期望值的反應有關聯，而這關聯是無關乎學習歷程的。

方法：本研究招募經過年紀與性別配對過的成人過動症患者與正常人各三十二名，請受試者在功能性磁振造影的過程中進行樂透抉擇測驗，受試者必須要每個回合不同可能輸或贏的機率下選擇是否要接受或是拒絕該回合的分數，我們針對受試者對於機率、分數以及交互作用的關係進行全腦神經迴路反應的探索。

結果：成人過動症患者相較正常人而言在中低可能贏的機率（或者說中高可能輸的機率）下會有較慢的反應時間以及接受比率較高的現象，尤其是在分數較高時。腦影像上則發現成人過動症患者比正常人對於機率的神經反應在內側顳葉上更為敏感，另外成人過動症患者只會在中到低機率的情況下發現情緒調控腦區的反應，相較之下正常人則是從高機率開始就發現情緒調控腦區的反應。整體來說，成人過動者患者較為冒險的行為與在內側顳葉較高的神經反應是有關聯的，然而卻與在背外側前額葉較低的神經反應有關聯。此外，成人過動症患者相較正常人在腹側紋狀體與腦島對於損失回饋有較高的反應。

結論：此研究認為成人過動症患者在不確定的選擇狀態以及面臨非預期的損失回饋下，容易選擇情感性而非直觀理性的神經歷程，這特徵或許可以成為未來進行過動症診斷的生物標記。

Background: Adults with ADHD tend to choose risky options in value-based decision behaviors. This study aims to evaluate whether adult ADHD risk-taking behavior is associated with altered sensitivity of involved neural circuits in frontal, striatal, and medial temporal areas to expected value (EV), apart from learning requirements. Methods: Thirty-two adults with ADHD and 32 healthy controls matched for age and gender underwent a Lottery Choice Task (LCT) in a functional magnetic resonance imaging (fMRI) experiment. Participants decided to accept or reject stakes that varied in the probability to win or lose different magnitudes of points constituting trial-wise EV. Analysis of brain functional data evaluated group differences in neural responses to probability, magnitude, and their interactions during choice and outcome phases. Results: Compared to healthy controls, adults with ADHD had slower reaction times and accepted more stakes with middle to low probability of winning (or middle to high probability of losing), particularly at high magnitudes. For neural responses, ADHD adults showed higher sensitivity to probability than controls in the medial temporal areas. ADHD patients also evinced regulatory processing only from middle to low probability stakes compared to regulation at higher probability stakes in healthy controls. In general, greater risk-taking behavior correlated with higher neural responses in medial temporal areas in ADHD but lower dorsolateral frontal responses in controls. Also, ADHD patients showed higher activation than normal controls in ventral striatum and insula to loss outcome. Conclusions: Our finding of recruiting affective neural processing rather than veridical neural processing in ambiguous condition during choice and unanticipated loss during outcome phase in adult ADHD may be potential biomarker for ADHD diagnosis.