運用功能性核磁共振及腦波同步量測探討模擬戰爭場景下之行為抑制網絡系統

Abstract

抑制能力現今主要分為兩種：認知上的抑制—主要為調控認知及專注力方面：行為上的抑制—具實際抑制行為上的控制(behavioral action)。藉由過去的研究我們了解到終止抑制實驗(stop signal task)已被廣泛的使用於探討行為抑制，然而不被過多的資訊干擾到純粹的抑制網絡系統，先前研究大多使用簡易符號於設計認知實驗，並充分探討腦功能與抑制網絡系統之關聯性。本研究將依據過去研究的發現，進一步探討如何轉譯認知功能上的發現於真實環境下所誘發出的抑制網絡系統，因此設計一具有威脅性的場景—戰爭場景(battlefield scenario)來了解真實環境下的行為抑制網絡系統。實驗設計上，本研究採用反恐精英遊戲為場景，設計以恐怖份子瞄準受試者（受試者須射擊恐怖份子）為反應作業，及設計恐怖份子挟持人質為抑制控制作業（受試者須停止射擊），探討受試者於生命威脅下的大腦抑制網絡系統，同時本研究亦進行傳統的終止抑制實驗(symbol scenario)進行比較。為能夠更加了解抑制網絡系統，本研究運用具備高空間解析度的功能性磁振造影儀(FMRI)與高時間解析度的腦波儀(EEG)同步收錄受試者的血氧濃度相依對比訊號與腦神經訊號。本研究結果發現兩種場景下可以發現右邊的下前額葉(right inferior frontal cortex, rIFC)，前運動補助區(pre-supplementary motor area, preSMA)等腦區的活化，然而這些腦區均被相關文獻證實與抑制功能相關。此外，本研究突破發現於戰爭場景下右顳頂交界區(right temporoparietal junction, rTPJ)及前運動補助區的θ頻帶跟

The stop-signal paradigm has been widely adopted as a way to parametrically quantify the response inhibition process. To evaluate inhibitory function in realistic environmental settings, the current study compared stop-signal responses in two different scenarios: One uses simple visual symbols as go and stop signals, and the other translates the typical design into a battlefield scenario where a sniper-scope view was the background, a terrorist image was the go signal, a hostage image was the stop signal, and the task instruction was to make a shooting response. The battlefield scenario created a threatening environment and allowed the evaluation of how participants’ inhibitory control manifest in this realistic stop-signal task. In order to investigate the participants’ brain activities with both high spatial and temporal resolution, simultaneous functional magnetic resonance imaging (FMRI) and electroencephalography (EEG) recordings were acquired. The results demonstrated that both scenarios induced increased activity in the right inferior frontal gyrus (IFG) and presupplementary motor area (preSMA), which have been linked to response inhibition. Notably, in right temporoparietal junction (rTPJ) we found both higher BOLD activation and synchronization of theta-alpha activities (4-12 Hz) in the battlefield scenario than in the traditional scenario after the stop signal. The higher activation of rTPJ in the battle-field scenario may be related to morality judgments or attentional reorienting. These results provided new insights into the complex brain networks involved in inhibitory control within naturalistic environments.