腦電圖研究結果揭示了恐懼如何在大腦中傳遞大綱

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Center for BrainHealth

大腦健康中心

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New research illustrates how fear arises in the brain when individuals are exposed to threatening images. This novel study is the first to separate emotion from threat by controlling for the dimension of arousal.

新研究闡述了大腦在人們看到威脅影像時如何產生恐懼情緒。這個新奇的研究首次通過控制喚醒的維度將威脅與情感分割開來。

An estimated 8% of Americans will suffer from post traumatic stress disorder (PTSD) at some point during their lifetime. Brought on by an overwhelming or stressful event or events, PTSD is the result of altered chemistry and physiology of the brain. Understanding how threat is processed in a normal brain versus one altered by PTSD is essential to developing effective interventions.

據估計約8%的的美國人在他們的某個時段會遭受創傷後應激障礙(PTSD)的折磨。由強悍而令人難以應對的或緊張的一個或多個事件所引發，PTSD是大腦化學上和生理上改變的結果。理解恐懼在一個正常的腦部活動中被PTSD改變對採取有效的干預是至關重要的。

New research from the Center for BrainHealth at The University of Texas at Dallas published online today in Brain and Cognition illustrates how fear arises in the brain when individuals are exposed to threatening images. This novel study is the first to separate emotion from threat by controlling for the dimension of arousal, the emotional reaction provoked, whether positive or negative, in response to stimuli. Building on previous animal and human research, the study identifies an electrophysiological marker for threat in the brain.

達拉斯德州大學的大腦健康中心今天在大腦和認知論壇上發佈了新研究，闡明瞭當人們看到威脅影像時，如何產生恐懼情緒。這個新奇的研究首次通過控制喚醒的維度將威脅與情感分割開來，無論是積極的還是消極的，情緒反應都是響應於刺激。基於之前對動物和人類的研究，該研究確定了一個反映大腦中威脅的電生理指標。

"We are trying to find where thought exists in the mind," explained John Hart, Jr., M.D., Medical Science Director at the Center for BrainHealth. "We know that groups of neurons firing on and off create a frequency and pattern that tell other areas of the brain what to do. By identifying these rhythms, we can correlate them with a cognitive unit such as fear."

“我們試圖發現想法存在於大腦中的位置，”大腦健康中心的醫學科學主任、醫學博士John Hart, Jr解釋道。“我們知道組神經元放電和停電時，會創建一個頻率和模式，告訴大腦的其他區域該做什麼。通過識別這些節律，我們能把它們與恐懼等認知單元相聯繫。”

Utilizing electroencephalography (EEG), Dr. Hart's research team identified theta and beta wave activity that signifies the brain's reaction to visually threatening images.

利用腦電圖(EEG)，哈特博士的研究小組發現了表示大腦對視覺威脅影響反應的θ和β波活動。

"We have known for a long time that the brain prioritizes threatening information over other cognitive processes," explained Bambi DeLaRosa, study lead author. "These findings show us how this happens. Theta wave activity starts in the back of the brain, in it's fear center -- the amygdala -- and then interacts with brain's memory center -- the hippocampus -- before traveling to the frontal lobe where thought processing areas are engaged. At the same time, beta wave activity indicates that the motor cortex is revving up in case the feet need to move to avoid the perceived threat."

“我們很早就知道大腦對威脅信息的敏感度要高於其他認知過程，”該研究的首席作者Bambi DeLaRosa解釋道。“這些發現向我們展示了它是如果發生的。θ波活動開始於位於大腦後部的恐懼中心——杏仁核——然後在前往思維加工區域，大腦額葉之前，與大腦記憶中心——海馬體——相互作用。同時，β波活動表明，在需要移動位置以避免威脅時，運動皮層加速加速運轉。”

For the study, 26 adults (19 female, 7 male), ages 19-30 were shown 224 randomized images that were either unidentifiably scrambled or real pictures. Real pictures were separated into two categories: threatening (weapons, combat, nature or animals) and non-threatening (pleasant situations, food, nature or animals).

在這項研究中，給予年齡在19歲到30歲之間的26個成年人(19個女性，7個男性) 224隨機影像，要麼是無法辨認的亂碼，要麼是真實的圖片。真實的圖片被分爲兩類：具有威脅性的(武器、戰鬥、自然或動物)和的不具有威脅性的(愉快的場景、食品、自然或動物)。

While wearing an EEG cap, participants were asked to push a button with their right index finger for real items and another button with their right middle finger for nonreal/scrambled items. Shorter response times were recorded for scrambled images than the real images. There was no difference in reaction time for threatening versus non-threatening images.

在戴着腦電圖帽的同時，參與者被要求用右手食指按下按鈕以看到真實圖片，另用右手中指按另一個按鈕以看到不真實的圖片或亂碼。亂碼圖像比真正的圖像記錄的響應時間更短。威脅性圖片和不具威脅性的圖片在反應時間上沒有差別。

EEG results revealed that threatening images evoked an early increase in theta activity in the occipital lobe (the area in the brain where visual information is processed), followed by a later increase in theta power in the frontal lobe (where higher mental functions such as thinking, decision-making, and planning occur). A left lateralized desynchronization of the beta band, the wave pattern associated with motor behavior (like the impulse to run), also consistently appeared in the threatening condition.

腦電圖結果表明威脅圖片誘發枕葉（大腦中處理視覺信息的區域）中的θ波活動早期增加，緊隨其後的是枕葉區域（更高級的心理機能，如思考、決策和計劃，在這裏發生）θ波的增加。β波左單側性的去同步化，與運動行爲(如脈衝運行)相關的波動行爲，也一再出現在威脅情況下。

This study will serve as a foundation for future work that will explore normal versus abnormal fear associated with an object in other atypical populations including individuals with PTSD.

本研究將成爲未來研究工作的基礎，將在其他非典型人羣中，包括在患有創傷後應激障礙的人羣中，探索與一個對象相聯繫的正常和不正常的恐懼。

This work was supported by the Berman Laboratory of Learning and Memory at The University of Texas at Dallas and the Jane and Bud Smith Distinguished Chair.

這項工作是達拉斯德州大學的學習和記憶伯曼實驗室、Jane和Bud Smith特聘教授提供支持。