School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
Biochem Biophys Res Commun. 2020 Apr 30;525(2):292-297. doi: 10.1016/j.bbrc.2020.02.077. Epub 2020 Feb 19.
'Fear neurons' in the basal amygdala (Ba) acquire excitatory responsiveness to conditioned stimuli (CS) after fear conditioning and are believed to encode aversive valence of conditioned fear. However, it is unclear whether identical fear conditioning sessions given at different times engage the same population of 'fear neurons'. Here, we recorded electrical activity from single neurons in the Ba while the same fear conditioning paradigm was performed at two different times. Conditioned fear was monitored during CS presentation after each conditioning session in order to identify 'fear neurons'. Surprisingly, we found that initial conditioning and re-conditioning recruited different populations of 'fear neurons' in the Ba. We performed a control experiment in which conditioned fear was monitored twice after a single fear conditioning session. The majority of the 'fear neurons', which were activated during the first retrieval, were re-activated during the second retrieval, suggesting that conditioning-induced 'fear neurons' are stable. Our findings, therefore, suggest that 'fear neurons' in the Ba encode specific learned events as well as their aversive valence.
基底杏仁核 (Ba) 中的“恐惧神经元”在恐惧条件反射后获得对条件刺激 (CS) 的兴奋性反应，并被认为编码条件恐惧的厌恶效价。然而，目前尚不清楚在不同时间进行相同的恐惧条件反射是否会涉及相同的“恐惧神经元”群体。在这里，我们在两次不同时间进行相同的恐惧条件反射范式时，记录了 Ba 中的单个神经元的电活动。在每次条件反射后，在 CS 呈现期间监测条件恐惧，以识别“恐惧神经元”。令人惊讶的是，我们发现初始条件反射和重新条件反射在 Ba 中招募了不同的“恐惧神经元”群体。我们进行了一项对照实验，其中在单次恐惧条件反射后两次监测条件恐惧。在第一次检索期间激活的大多数“恐惧神经元”在第二次检索期间再次被激活，这表明条件反射诱导的“恐惧神经元”是稳定的。因此，我们的发现表明，Ba 中的“恐惧神经元”不仅编码特定的学习事件，还编码其厌恶效价。
