Neural timescales reflect behavioral demands in freely moving rhesus macaques

Previous work demonstrated a highly reproducible cortical hierarchy of
neural timescales at rest, with sensory areas displaying fast, and
higher-order association areas displaying slower timescales. The question
arises as to how such stable hierarchies give rise to adaptive behavior
that requires flexible adjustment of temporal coding and integration
demands. Potentially, this lack of variability in the hierarchical
organization of neural timescales could reflect the structure of the
laboratory contexts. We posit that unconstrained paradigms are ideal to
test whether the dynamics of neural timescales reflect behavioral demands.
Here we measured timescales of local field potential activity while male
rhesus macaques foraged in an open space. We found a hierarchy of neural
timescales that differs from previous work. Importantly, although the
magnitude of neural timescales expanded with task engagement, the brain
areas’ relative position in the hierarchy was stable. Next, we
demonstrated that the change in neural timescales is dynamic and contains
functionally relevant information, differentiating between similar events
in terms of motor demands and associated rewards. Finally, we demonstrated
that brain areas are differentially affected by these behavioral demands.
These results demonstrate that while the space of neural timescales is
anatomically constrained, the observed hierarchical organization and
magnitude are dependent on behavioral demands.