Endogenous Modulation of Low Frequency Oscillations by Temporal Expectations

Abstract

Recent studies have associated increasing temporal expectations with synchronization of higher frequency oscillations and suppression of lower frequencies. In this experiment, we explore a proposal that low-frequency oscillations provide a mechanism for regulating temporal expectations. We used a speeded Go/No-go task and manipulated temporal expectations by changing the probability of target presentation after certain intervals. Across two conditions, the temporal conditional probability of target events differed substantially at the first of three possible intervals. We found that reactions times differed significantly at this first interval across conditions, decreasing with higher temporal expectations. Interestingly, the power of theta activity (4-8 Hz), distributed over central midline sites, also differed significantly across conditions at this first interval. Furthermore, we found a transient coupling between theta phase and beta power after the first interval in the condition with high temporal expectation for targets at this time point. Our results suggest that the adjustments in theta power and the phase-power coupling between theta and beta contribute to a central mechanism for controlling neural excitability according to temporal expectations.

Note:
Funding Information: This work was supported by Wellcome Trust project grant (to A. C. Nobre). G. Rohenkohl was partially supported by Programme Alban (the European Union Programme of High Level Scholarship for Latin America No. E07D403637BR). A. M. Cravo was supported by Fundação de Amparo a` Pesquisa do Estado de São Paulo (FAPESP) and CAPES. V. Wyart was supported by the Fyssen Foundation.

Declaration of Interests: No conflicts of interest, financial or otherwise, are declared by the author(s).

Ethics Approval Statement: All experimental methods had ethical approval from the Central University Research Ethics Committee of the University of Oxford. Participants gave informed consent to take part in the experiment.

Keywords: Temporal expectations; phase-power coupling; neural oscillations