School of Biological Sciences, Seoul National University, Gwanak-gu, Seoul 08826, South Korea.
Science. 2018 Apr 27;360(6387):430-435. doi: 10.1126/science.aas9204.
Memory resides in engram cells distributed across the brain. However, the site-specific substrate within these engram cells remains theoretical, even though it is generally accepted that synaptic plasticity encodes memories. We developed the dual-eGRASP (green fluorescent protein reconstitution across synaptic partners) technique to examine synapses between engram cells to identify the specific neuronal site for memory storage. We found an increased number and size of spines on CA1 engram cells receiving input from CA3 engram cells. In contextual fear conditioning, this enhanced connectivity between engram cells encoded memory strength. CA3 engram to CA1 engram projections strongly occluded long-term potentiation. These results indicate that enhanced structural and functional connectivity between engram cells across two directly connected brain regions forms the synaptic correlate for memory formation.
记忆驻留在分布于整个大脑的记忆细胞中。然而，这些记忆细胞中的特定位置仍然是理论上的，尽管普遍认为突触可塑性编码了记忆。我们开发了双 eGRASP（跨越突触伙伴的绿色荧光蛋白重组）技术，以研究记忆细胞之间的突触，以确定记忆存储的特定神经元位置。我们发现，从 CA3 记忆细胞接收输入的 CA1 记忆细胞上的棘突数量和大小增加。在情境性恐惧条件反射中，这种增强的记忆细胞间连接编码了记忆强度。CA3 记忆细胞到 CA1 记忆细胞的投射强烈阻止了长时程增强。这些结果表明，两个直接连接的脑区之间的记忆细胞之间增强的结构和功能连接形成了记忆形成的突触相关物。
