Machado Christopher J, Kazama Andy M, Bachevalier Jocelyne
Department of Neurobiology and Anatomy, University of Texas Health Science Center, USA.
Emotion. 2009 Apr;9(2):147-63. doi: 10.1037/a0014539.
The authors measured the effects of bilateral amygdaloid, orbital frontal, or hippocampal lesions on emotional reactivity and passive avoidance in rhesus monkeys (Macaca mulatta). Animals were presented with 8 neutral or 8 aversive objects, each paired with a highly preferred food reward. Sham-operated control animals displayed heightened defensive behaviors and typically would not approach or retrieve the food when paired with a potential predator (coiled rubber snake), 2 conditioned aversive stimuli for laboratory-housed monkeys (a capture net and leather handling gloves), and 1 object displaying a threatening social signal (direct eye contact from a human-like doll). Animals with amygdala lesions, but not hippocampal or orbital frontal lesions, showed less tension-related behaviors and diminished passive avoidance of the rubber snake and its matched neutral item (a coiled piece of hose) relative to control animals. All operated groups displayed normal patterns of behavior toward conditioned and socially aversive objects. These results expand our understanding of how the primate brain evaluates reward and threat, and indicate a highly specialized role for the amygdala in mediating passive avoidance and emotional reactivity to potentially life-threatening stimuli.
作者们测量了双侧杏仁核、眶额叶或海马体损伤对恒河猴（猕猴）情绪反应性和被动回避行为的影响。给动物呈现8个中性物体或8个厌恶物体，每个物体都与一种非常喜欢的食物奖励配对。假手术对照组动物表现出增强的防御行为，当与潜在捕食者（盘绕的橡胶蛇）、实验室饲养猴子的2种条件性厌恶刺激物（捕获网和皮革处理手套）以及1个显示威胁性社会信号的物体（类人玩偶的直接眼神接触）配对时，通常不会接近或获取食物。与对照组动物相比，杏仁核损伤的动物，但海马体或眶额叶未损伤的动物，表现出与紧张相关的行为减少，对橡胶蛇及其匹配的中性物体（一段盘绕的软管）的被动回避减弱。所有手术组对条件性和社会性厌恶物体都表现出正常的行为模式。这些结果扩展了我们对灵长类大脑如何评估奖励和威胁的理解，并表明杏仁核在介导对潜在危及生命刺激的被动回避和情绪反应方面具有高度专业化的作用。
