A central question in neuroscience is how synaptic plasticity shapes the feature selectivity of neurons in behaving animals¹. Hippocampal CA1 pyramidal neurons display one of the most striking forms of feature selectivity by forming spatially and contextually selective receptive fields called place fields, which serve as a model for studying the synaptic basis of learning and memory. Various forms of synaptic plasticity have been proposed as cellular substrates for the emergence of place fields. However, despite decades of work, our understanding of how synaptic plasticity underlies place-field formation and memory encoding remains limited, largely due to a shortage of tools and technical challenges associated with the visualization of synaptic plasticity at the single-neuron resolution in awake behaving animals. To address this, we developed an all-optical approach to monitor the spatiotemporal tuning and synaptic weight changes of dendritic spines before and after the induction of a place field in single CA1 pyramidal neurons during spatial navigation. We identified a temporally asymmetric synaptic plasticity kernel resulting from bidirectional modifications of synaptic weights around the induction of a place field. Our work identified compartment-specific differences in the magnitude and temporal expression of synaptic plasticity between basal dendrites and oblique dendrites. Our results provide experimental evidence linking synaptic plasticity to the rapid emergence of spatial selectivity in hippocampal neurons, a critical prerequisite for episodic memory.

神经科学的一个中心问题是突触可塑性如何塑造行为动物神经元的特征选择性¹。海马 CA1 锥体神经元通过形成称为位置场的空间和环境选择性感受野来显示最引人注目的特征选择性形式之一，该感受野作为研究学习和记忆的突触基础的模型。各种形式的突触可塑性已被提议作为地方场出现的细胞底物。然而，尽管进行了数十年的工作，我们对突触可塑性如何成为位置场形成和记忆编码的基础的理解仍然有限，这主要是由于缺乏工具和与清醒行为动物的单神经元分辨率突触可塑性可视化相关的技术挑战。为了解决这个问题，我们开发了一种全光学方法来监测空间导航期间单个 CA1 锥体神经元中位置场诱导前后树突棘的时空调整和突触权重变化。我们确定了一个时间不对称的突触可塑性核，这是由围绕位置场诱导的突触权重的双向修改引起的。我们的工作确定了基底树突和斜树突之间突触可塑性的大小和时间表达的区室特异性差异。我们的结果提供了实验证据，将突触可塑性与海马神经元空间选择性的快速出现联系起来，这是情景记忆的关键先决条件。