Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
Stanford University, Stanford, CA, USA.
Nat Neurosci. 2021 Feb;24(2):259-265. doi: 10.1038/s41593-020-00776-3. Epub 2021 Jan 25.
Short-term memory is associated with persistent neural activity that is maintained by positive feedback between neurons. To explore the neural circuit motifs that produce memory-related persistent activity, we measured coupling between functionally characterized motor cortex neurons in mice performing a memory-guided response task. Targeted two-photon photostimulation of small (<10) groups of neurons produced sparse calcium responses in coupled neurons over approximately 100 μm. Neurons with similar task-related selectivity were preferentially coupled. Photostimulation of different groups of neurons modulated activity in different subpopulations of coupled neurons. Responses of stimulated and coupled neurons persisted for seconds, far outlasting the duration of the photostimuli. Photostimuli produced behavioral biases that were predictable based on the selectivity of the perturbed neuronal population, even though photostimulation preceded the behavioral response by seconds. Our results suggest that memory-related neural circuits contain intercalated, recurrently connected modules, which can independently maintain selective persistent activity.
短期记忆与持续的神经活动有关，而这种持续的神经活动是由神经元之间的正反馈维持的。为了探索产生与记忆相关的持续活动的神经回路基元，我们在执行记忆引导反应任务的小鼠中测量了功能特征明确的运动皮层神经元之间的耦合。靶向双光子光刺激小（<10）组神经元，在大约 100μm 的范围内，在偶联神经元中产生稀疏的钙反应。具有相似任务相关选择性的神经元优先偶联。不同神经元群的光刺激调制了偶联神经元中不同亚群的活动。刺激和偶联神经元的反应持续数秒，远远超过光刺激的持续时间。光刺激产生了基于受干扰神经元群体选择性的可预测的行为偏差，即使光刺激比行为反应提前了数秒。我们的结果表明，与记忆相关的神经回路包含交错的、递归连接的模块，这些模块可以独立维持选择性的持续活动。
