Jill K. Leutgeb

Abstract Working memory (WM) is essential for performing cognitive tasks, and sequentially active hippocampal cells over many seconds (‘time cells’) have been observed during WM retention. Time cells predominantly occur when neural activity oscillates at theta frequency.

Introduction Brain oscillations are thought to coordinate neural computations across cortical and sub-cortical brain regions by synchronizing network activity (Buzsaki and Draguhn, 2004). For example, coordination in the theta frequency range (6–12 Hz) is prominent in neural circuits that support memory function, and accordingly, theta oscillations are not only found in the hippocampus, but also in directly and indirectly connected brain regions (Buzsaki, 2002; Colgin, 2011; Backus et al., 2016).

Abstract Mental exploration enables flexible evaluation of potential future choices, guiding decision-making without requiring direct real-world iterations. Although the hippocampus is known to be active while imagining the future, the precise mechanisms that support mental exploration of future choices remain unclear.