Dynamic gain control of aversive signals enables adaptive behavioral responses. Although the role of amygdalar circuits in aversive processing is well established, the neural pathway for amplifying aversion remains elusive. Here, we show that the brainstem circuit linking the interpeduncular nucleus (IPN) with the nucleus incertus (NI) amplifies aversion and promotes avoidant behaviors. IPN GABA neurons are activated by aversive stimuli and their predicting cues, with their response intensity closely tracking aversive values. Activating these neurons does not trigger aversive behavior on its own but rather amplifies responses to aversive stimuli, whereas their ablation or inhibition suppresses such responses. Detailed circuit dissection revealed anatomically distinct subgroups within the IPN GABA neuron population, highlighting the NI-projecting subgroup as the modulator of aversiveness related to fear and opioid withdrawal. These findings unveil the IPN-NI circuit as an aversion amplifier and suggest potential targets for interventions against affective disorders and opioid relapse.

中文翻译：

---

脑干回路放大了厌恶


厌恶信号的动态增益控制可实现自适应行为响应。尽管杏仁核回路在厌恶加工中的作用已得到充分证实，但放大厌恶的神经通路仍然难以捉摸。在这里，我们表明连接蒂间核 （IPN） 和不稳核 （NI） 的脑干回路放大了厌恶并促进了回避行为。IPN GABA 神经元被厌恶刺激及其预测线索激活，它们的反应强度与厌恶值密切相关。激活这些神经元本身不会触发厌恶行为，而是会放大对厌恶刺激的反应，而它们的消融或抑制会抑制这种反应。详细的电路解剖揭示了 IPN GABA 神经元群中解剖学上不同的亚组，突出了 NI 投射亚组作为与恐惧和阿片类药物戒断相关的厌恶的调节剂。这些发现揭示了 IPN-NI 回路作为厌恶放大器，并提出了针对情感障碍和阿片类药物复发的干预的潜在目标。