一項研究發(fā)現(xiàn),，人類大腦可能根據(jù)威脅物的接近程度、軌跡以及對其的預期從而對其做出不同的反應,。Dean Mobbs及其同事使用功能磁共振成像（fMRI）觀察了20位實驗參與者的大腦活動,，當時參與者們在觀看他們認為是科學家把一個捕鳥蛛放在每位參與者腳邊的實時視頻。
盡管這些視頻其實是預先錄制的,，這些參與者認為這個蜘蛛是放在了6個隔間中的1個,，由這組科學家操縱誘使這只蜘蛛爬向或者爬離每位參與者。參與者報告了在整個實驗期間他們預期的和真實的恐懼體驗,。這組作者觀察到,，無論捕鳥蛛與參與者的絕對距離是多少，當捕鳥蛛慢慢接近而不是撤退的時候,，大腦的恐慌反應中心出現(xiàn)了更大的活動,，參與者也報告了更大的恐懼。
這組作者報告說,，一些大腦區(qū)域活動的漲落是根據(jù)蜘蛛的軌跡,，而另外一些區(qū)域僅僅在極端恐懼或蜘蛛距離參與者最遠的時候才有反應。這些結(jié)果提示,，大腦的“恐懼網(wǎng)絡”的不同組件有不同的威脅-響應功能,。此外這組作者說，這一信息可能會幫助科學家診斷和治療臨床恐懼癥的患者,。（生物谷Bioon.com）
生物谷推薦英文摘要：
PNAS doi: 10.1073/pnas.1009076107
Neural activity associated with monitoring the oscillating threat value of a tarantula
Dean Mobbsa,1, Rongjun Yua, James B. Rowea,b, Hannah Eicha, Oriel FeldmanHalla, and Tim Dalgleisha
aCognition and Brain Sciences Unit, Medical Research Council-Cognition and Brain Sciences Unit, Cambridge CB2 7EF, United Kingdom; and
bDepartment of Clinical Neurosciences, University of Cambridge, Cambridge CB2 2QQ, United Kingdom
Phylogenetic threats such as spiders evoke our deepest primitive fears. When close or looming, such threats engage evolutionarily conserved monitoring systems and defense reactions that promote self-preservation. With the use of a modified behavioral approach task within functional MRI, we show that, as a tarantula was placed closer to a subject's foot, increased experiences of fear coincided with augmented activity in a cascade of fear-related brain networks including the periaqueductal gray, amygdala, and bed nucleus of the stria terminalis. Activity in the amygdala was also associated with underprediction of the tarantula's threat value and, in addition to the bed nucleus of the stria terminalis, with monitoring the tarantula's threat value as indexed by its direction of movement. Conversely, the orbitofrontal cortex was engaged as the tarantula grew more distant, suggesting that this region emits safety signals or expels fear. Our findings fractionate the neurobiological mechanisms associated with basic fear and potentially illuminate the perturbed reactions that characterize clinical phobias.
