Frontocentral Neural Dynamics Reflect Decisions about When to Act

Voluntary actions result from a series of decisions about how and when to interact with the world. This decision-making process requires integrating and interpreting sensory information from the environment with prior experiences and internal states. Decisions are not solely about what to do, but also when to do it. To do this, the brain must represent time internally and use that representation to trigger actions at appropriate moments. By leveraging temporal cues from the environment, agents can prepare actions in advance, synchronize with external events, and rely on prior experiences to act effectively (Buhusi and Meck, 2005; Nobre and van Ede, 2018). A wide body of work has explored how the brain tracks interval durations, anticipates upcoming events, and calibrates the timing of actions. These include the entrainment of neural oscillations to external rhythms, changes in the geometry and speed of population dynamics in regions such as the basal ganglia and supplementary motor area, and slow ramping activity in frontocentral cortex (Tsao et al., 2022). Ramping activity, sometimes referred to as the readiness potential, reflects a gradual buildup of neural activity preceding voluntary movement and is thought to encode the passage of time toward an internally defined threshold (Schurger et al., 2021). Similar ramp-like dynamics have also been observed in decision-making paradigms, where evidence is accumulated until a decision boundary is reached (Fig. 1 A ; Ratcliff, 2002; Schall, 2019). These ramp-to-threshold models may offer a common computational framework linking when to act with what action to select. Indeed, both timing and decision-making can be described as forms of evidence accumulation—one integrating elapsed time, the other sensory information—culminating in threshold crossing that triggers an action or decision. Figure 1. Activity in neural and cognitive models of decision-making during response time (RT) tasks. A , Left, Schematic illustration of an accumulator … Correspondence should be addressed to Steven P. Errington at steven.errington{at}newcastle.ac.uk.