一項新的研究結(jié)果顯示了人腦在一項恐懼條件反射實驗期間的焦慮狀況,，并揭示了為何有些人更容易或者更不容易罹患焦慮癥,。
這項發(fā)表在《神經(jīng)元》Neuron 月刊2月號上的研究結(jié)果揭示,，神經(jīng)機制可能與抵抗病理性恐懼和焦慮的能力相關(guān),。這項發(fā)現(xiàn)或許有助于改進慢性焦慮癥的治療方法,，也有助于指導危險個體找到避免罹患焦慮癥的方法。
此前的一些研究結(jié)果顯示扁桃核這一腦結(jié)構(gòu)與獲得和表達條件性恐懼有關(guān),。條件性恐懼指某種刺激(條件刺激)變得與某個令人厭惡的物體或者事件(無條件刺激)相關(guān)的狀況,。研究結(jié)果顯示，不管在動物還是人體內(nèi),，另一個腦區(qū)域——腹內(nèi)側(cè)前額葉皮質(zhì)都有助于在恐懼消退訓練后阻止條件性恐懼,。恐懼消退訓練指不斷發(fā)出條件刺激,，卻不呈現(xiàn)無條件刺激,。
這項研究報告的高級作者、美國加利福尼亞大學伯克利分校的索尼婭·J·畢曉普博士解釋說：“我們對為何有些人能比其他人更容易克服在生活中經(jīng)歷的個別恐懼和非特定焦慮有興趣,。換句話說,，要確定腦功能上的哪些區(qū)別可能導致某些人更容易罹患慢性恐懼和焦慮癥。”
畢曉普及其同事開展了一項神經(jīng)成像項目來研究人的恐懼條件反射,。這些研究對象被歸為具有不同程度“個性焦慮”的一類人,，他們具有在一系列日常環(huán)境中發(fā)生焦慮的傾向。研究人員發(fā)現(xiàn),，個性焦慮程度高的研究對象的扁桃核更可能對條件刺激恐懼暗示作出強烈反應,，并顯示能更快地獲取這些暗示的“習得性恐懼”。（生物谷Bioon.com）
生物谷推薦原文出處：
Neuron doi:10.1016/j.neuron.2010.12.034
Fear-Conditioning Mechanisms Associated with Trait Vulnerability to Anxiety in Humans
Iole Indovina, Trevor W. Robbins, Anwar O. Nú?ez-Elizalde, Barnaby D. Dunn, Sonia J. Bishop
Summary
Investigations of fear conditioning in rodents and humans have illuminated the neural mechanisms underlying cued and contextual fear. A critical question is how personality dimensions such as trait anxiety act through these mechanisms to confer vulnerability to anxiety disorders, and whether humans' ability to overcome acquired fears depends on regulatory skills not characterized in animal models. In a neuroimaging study of fear conditioning in humans, we found evidence for two independent dimensions of neurocognitive function associated with trait vulnerability to anxiety. The first entailed increased amygdala responsivity to phasic fear cues. The second involved impoverished ventral prefrontal cortical (vPFC) recruitment to downregulate both cued and contextual fear prior to omission (extinction) of the aversive unconditioned stimulus. These two dimensions may contribute to symptomatology differences across anxiety disorders; the amygdala mechanism affecting the development of phobic fear and the frontal mechanism influencing the maintenance of both specific fears and generalized anxiety.
