右側前島葉網絡對過動症成人執行抑制控制作業之影響：數字Stroop測驗的功能性磁振造影研究

Right Anterior Insula Network for Inhibitory Control in ADHD Adults: A Counting Stroop fMRI Study

陳端慶(Tuan-Ching Chen)

指導教授 ： 周泰立

國立臺灣大學/醫學院/腦與心智科學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202001998

摘要

抑制控制能力為人類基於大腦認知資源有限情形下，抑制衝突訊號，以便大腦將資源聚焦處理與目標相關資訊之能力。過去研究指出，過動症患者之抑制控制功能具明顯缺損，且相較健康人會出現額下迴（inferior frontal gyrus, IFG）及前扣帶皮層（anterior cingulate cortex, ACC）異常活化之情形，然近期健康人研究進一步指出，除額下迴及前扣帶皮層外，大腦右側前島葉（right anterior insula, rAI）亦為參與抑制控制歷程重要區域，因此，本研究旨在探討前島葉網絡對過動症成人執行抑制控制作業之影響。透過功能性磁振造影搭配數字Stroop作業(counting Stroop Task)，本研究檢驗25位過動症成人及26位健康成人執行抑制控制功能之神經機制。在數字Stroop作業中，畫面會出現個數1至4不等之國字，受試者需判斷國字個數並以按件反應，其中，國字本身所代表語意訊息可能與出現個數相符（一致）、不符（不一致），或語意訊息與不包含個數訊息（控制）。研究結果顯示，過動症成人之右側前島葉及兩側額下迴活化均較健康成人為高且達到統計顯著，且右側前島葉活化程度與反應時間成正相關。功能性連結分析進一步顯示，在執行抑制控制能力時，健康成人的右側前島葉會與前扣帶皮層連結，但過動症成人的右側前島葉並未連向前扣帶皮層，反而係與左側額下迴連結，且此異常連結強度與過動成人症狀呈正相關。本研究認為，過動症患者抑制控制能力之缺損應與右側前島葉功能異常，以及右側前島葉功能性網絡失常具密切關連。

關鍵字

過動症 ； 數字Stroop測驗 ； 功能性磁振造影 ； 功能性連結 ； 抑制控制

並列摘要

Inhibitory control is the ability to withhold or override certain mental processes with or without intention, conceptualized as mental suppression of competing information due to our limited cognitive capacity. Past findings have shown deficits in inhibitory control ability in patients with Attention-Deficit/Hyperactivity Disorder (ADHD), with the inferior frontal gyrus (IFG) and anterior cingulate cortex (ACC) being considered the two primary brain regions responsible for inhibition. However, recent studies in healthy adults have shown that the right anterior insula (AI), a region showing proximity with the IFG, was also crucially involved in inhibition processes. Therefore, the present study aimed to further delineate the role right AI and its network play for inhibitory control in ADHD group. 26 healthy control (HC) adults (mean age=24, S.D.=5.5) and 25 ADHD adults (mean age=26, S.D.=8.3) were recruited to perform the counting Stroop task while scanned in the fMRI. Additional clinical and neuropsychological tests, including SNAP-IV scale, and Rapid Visual Processing task (RVP), were also conducted outside the scanner. Our results showed that the ADHD group had greater right AI and bilateral IFG activation than the HC group during inhibition task. In addition, greater right AI activation was positively correlated with the reaction time of the incongruent condition in the counting Stroop task and mean latency of the RVP test, suggesting a functional inefficiency in the right AI for ADHD group. Furthermore, our PPI results reveal that the right insula in HC group tend to have stronger functional connectivity with the right ACC, while the right insula in the ADHD group tend to have stronger functional connectivity with the left IFG, but not the right ACC; on top of that, the stronger the connectivity between the right AI and left IFG in ADHD group, the more severe ADHD symptom would be. Our findings indicate that abnormal insula network might lead to abnormal functional synchronization between the insula and IFG, interfering the proper salience network and inhibition function, and thus contribute to the deficits in ADHD inhibitory control performance.

並列關鍵字

attention-deficit/hyperactivity disorder ； counting Stroop fMRI ； functional connectivity ； inhibitory control

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