Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark.
Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark.
Cell Rep. 2024 Aug 27;43(8):114468. doi: 10.1016/j.celrep.2024.114468. Epub 2024 Aug 5.
Engrams, which are cellular substrates of memory traces, have been identified in various brain areas, including the amygdala. While most identified engrams are composed of excitatory, glutamatergic neurons, GABAergic inhibitory engrams have been relatively overlooked. Here, we report the identification of an inhibitory engram in the central lateral amygdala (CeL), a key area for auditory fear conditioning. This engram is primarily composed of GABAergic somatostatin-expressing (SST(+)) and, to a lesser extent, protein kinase C-δ-expressing (PKC-δ(+)) neurons. Fear memory is accompanied by a preferential enhancement of synaptic inhibition onto PKC-δ(+) neurons. Silencing this CeL GABAergic engram disinhibits the activity of targeted extra-amygdaloid areas, selectively increasing the expression of fear. Our findings define the behavioral function of an engram formed exclusively by GABAergic inhibitory neurons in the mammalian brain.
记忆痕迹的细胞基础即记忆印迹，已在包括杏仁核在内的多个脑区中被识别。虽然大多数已鉴定的记忆印迹由兴奋性谷氨酸能神经元组成，但 GABA 能抑制性记忆印迹相对被忽视。在此，我们报告了在中央外侧杏仁核（CeL）中发现了一个抑制性记忆印迹，CeL 是听觉恐惧条件反射的关键区域。这个记忆印迹主要由 GABA 能生长抑素表达（SST(+))神经元组成，在较小程度上由蛋白激酶 C-δ 表达（PKC-δ(+))神经元组成。恐惧记忆伴随着突触抑制对 PKC-δ(+)神经元的优先增强。沉默这个 CeL GABA 能记忆印迹会解除对靶向外侧杏仁核区域的抑制，选择性地增加恐惧的表达。我们的发现定义了在哺乳动物大脑中由 GABA 能抑制性神经元组成的记忆印迹的行为功能。
