Neurons in the medial prefrontal cortex (mPFC) are functionally linked to working memory (WM) but how distinct projection pathways contribute to WM remains unclear. Based on optical recordings, optogenetic perturbations, and pharmacological interventions in male mice, we report here that dorsomedial striatum (dmStr)-projecting mPFC neurons are essential for WM maintenance, but not encoding or retrieval, in a T-maze spatial memory task. Fiber photometry of GCaMP6m-labeled mPFC→dmStr neurons revealed strongest activity during the maintenance period, and optogenetic inhibition of these neurons impaired performance only when applied during this period. Conversely, enhancing mPFC→dmStr pathway activity—via pharmacological suppression of HCN1 or by optogenetic activation during the maintenance period—alleviated WM impairment induced by NMDA receptor blockade. Moreover, cellular-resolution miniscope imaging revealed that >50% of mPFC→dmStr neurons are active during WM maintenance and that this subpopulation is distinct from neurons active during encoding and retrieval. In all task periods, neuronal sequences were evident. Striatum-projecting mPFC neurons thus critically contribute to spatial WM maintenance.

内侧前额叶皮层 (mPFC) 中的神经元在功能上与工作记忆 (WM) 相关，但不同的投射路径如何影响工作记忆仍不清楚。基于雄性小鼠的光学记录、光遗传学扰动和药理干预，我们在此报告，在 T 迷宫空间记忆任务中，背内侧纹状体 (dmStr) 投射的 mPFC 神经元对于 WM 维持至关重要，但对编码或检索不是必需的。GCaMP6m 标记的 mPFC→dmStr 神经元的光纤光度测定显示，在维持期间活性最强，并且仅在此期间应用这些神经元的光遗传学抑制才会损害性能。相反，通过药理学抑制 HCN1 或在维持期间通过光遗传学激活来增强 mPFC→dmStr 通路活性，可减轻 NMDA 受体阻断引起的 WM 损伤。此外，细胞分辨率微型显微镜成像显示，>50% 的 mPFC→dmStr 神经元在 WM 维持期间处于活跃状态，并且该亚群与在编码和检索期间活跃的神经元不同。在所有任务期间，神经元序列都很明显。因此，纹状体投射的 mPFC 神经元对空间 WM 的维持至关重要。