海马尖波-涟漪后腹侧纹状体多巴胺升高

Summary The reactivation of task-related hippocampal activity during sharp-wave ripples (SWRs), often expressed as sequential “replay,” is thought to contribute to behavior through both online and offline processes. During sleep and awake rest, replay supports memory consolidation, broadly defined as the updating and stabilization of knowledge structures for later use. During active task engagement, replay may also support decision-making through episodic memory retrieval and the generation of prospective scenarios 1–4 (but see 5 ). While disrupting SWR events impairs memory-guided behavior 6–9 and augmenting them enhances such behavior 10,11 , the neurophysiological mechanisms that enable replay to contribute to behavior remain unclear. Theories of replay-based learning posit the need for replay events to be followed by an evaluative signal. Dopamine (DA) is consistently associated with such teaching signals, particularly in the ventral striatum, where it reflects reward- and other prediction-error signals 12 . Although hippocampal activity can influence mesolimbic dopamine signaling 13–15 , whether SWRs are coupled to ventral striatal DA release is unknown. To address this, we simultaneously recorded dorsal CA1 local field potentials to detect SWRs and measured ventral striatal DA concentration using fiber photometry of the GRAB DA2m sensor 16 in freely moving mice. We found a significant increase in DA following SWRs. This coupling was more prominent during offline rest than during periods of immobility during behavior, and was stronger following longer and higher-power SWRs. These results reveal coupling between hippocampal SWRs and striatal dopamine, providing a potential candidate mechanism through which internally generated hippocampal activity could engage evaluative signals during offline memory processing.