一項(xiàng)研究發(fā)現(xiàn),,人類(lèi)大腦可能根據(jù)威脅物的接近程度,、軌跡以及對(duì)其的預(yù)期從而對(duì)其做出不同的反應(yīng),。Dean Mobbs及其同事使用功能磁共振成像(fMRI)觀察了20位實(shí)驗(yàn)參與者的大腦活動(dòng),,當(dāng)時(shí)參與者們?cè)谟^看他們認(rèn)為是科學(xué)家把一個(gè)捕鳥(niǎo)蛛放在每位參與者腳邊的實(shí)時(shí)視頻,。
盡管這些視頻其實(shí)是預(yù)先錄制的,,這些參與者認(rèn)為這個(gè)蜘蛛是放在了6個(gè)隔間中的1個(gè),,由這組科學(xué)家操縱誘使這只蜘蛛爬向或者爬離每位參與者。參與者報(bào)告了在整個(gè)實(shí)驗(yàn)期間他們預(yù)期的和真實(shí)的恐懼體驗(yàn),。這組作者觀察到,,無(wú)論捕鳥(niǎo)蛛與參與者的絕對(duì)距離是多少,當(dāng)捕鳥(niǎo)蛛慢慢接近而不是撤退的時(shí)候,,大腦的恐慌反應(yīng)中心出現(xiàn)了更大的活動(dòng),,參與者也報(bào)告了更大的恐懼。
這組作者報(bào)告說(shuō),,一些大腦區(qū)域活動(dòng)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(yuǎn)的時(shí)候才有反應(yīng)。這些結(jié)果提示,,大腦的“恐懼網(wǎng)絡(luò)”的不同組件有不同的威脅-響應(yīng)功能,。此外這組作者說(shuō),這一信息可能會(huì)幫助科學(xué)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.