For the past 30 years, research on the amygdala has largely focused on the genesis of defensive behaviors as its main function. This focus originated from early lesion studies and was supported by extensive anatomical, physiological, and pharmacological data. Here we argue that while much data is consistent with the fear model of amygdala function, it has never been directly tested, in part due to overreliance on the fear conditioning task. In support of the fear model, amygdala neurons appear to signal threats and/or stimuli predictive of threats. However, recent studies in a natural threat setting show that amygdala activity does not correlate with threats, but simply with the movement of the rat, independent of valence. This was true for both natural threats as well as conditioned stimuli; indeed there was no evidence of threat signaling in amygdala neurons. Similar findings are emerging for prefrontal neurons that modulate the amygdala. These recent developments lead us to propose a new conceptualization of amygdala function whereby the amygdala inhibits behavioral engagement. Moreover, we propose that the goal of understanding the amygdala will be best served by shifting away from fear conditioning toward naturalistic approach and avoidance paradigms that involve decision-making and a larger repertoire of spontaneous and learned behaviors, all the while keeping an open mind.

在过去的30年中，对杏仁核的研究主要集中在防御行为的产生上，这是其主要功能。该焦点源自早期病变研究，并得到大量解剖学，生理学和药理学数据的支持。在这里，我们认为，尽管许多数据与杏仁核功能的恐惧模型相符，但从未对其进行过直接测试，部分原因是过度依赖恐惧调节任务。为了支持恐惧模型，杏仁核神经元似乎发信号通知威胁和/或预示威胁的刺激。但是，最近在自然威胁环境中进行的研究表明，杏仁核的活动与威胁无关，而仅与大鼠的运动无关，与化合价无关。无论是自然威胁还是条件刺激，都是如此。实际上，没有证据表明杏仁核神经元中存在威胁信号。调节杏仁核的前额神经元也出现了类似的发现。这些最新发展使我们提出了杏仁核功能的新概念，其中杏仁核抑制了行为参与。此外，我们建议，最好的理解杏仁核的方法是，从恐惧条件转变为自然主义方法和避免范式，后者涉及决策以及更大范围的自发性和学习行为，同时保持开放的态度。