Alejandro O. Blenkmann

Ramping dynamics and theta oscillations reflect dissociable signatures during rule-guided human behavior

abstract:

Contextual cues and prior evidence guide human goal-directed behavior. The neurophysiological mechanisms that implement contextual priors to guide subsequent actions in the human brain remain unclear. Using intracranial electroencephalography (iEEG), we demonstrate that increasing uncertainty introduces a shift from a purely oscillatory to a mixed processing regime with an additional ramping component. Oscillatory and ramping dynamics reflect dissociable signatures, which likely differentially contribute to the encoding and transfer of different cognitive variables in a cue-guided motor task. The results support the idea that prefrontal activity encodes rules and ensuing actions in distinct coding subspaces, while theta oscillations synchronize the prefrontal-motor network, possibly to guide action execution. Collectively, our results reveal how two key features of large-scale neural population activity, namely continuous ramping dynamics and oscillatory synchrony, jointly support rule-guided human behavior.

Authors:

  • Jan Weber

  • Anne-Kristin Solbakk

  • Alejandro O. Blenkmann

  • Anais Llorens

  • Ingrid Funderud

  • Sabine Leske

  • Pål Gunnar Larsson

  • Lugoslav Ivanovic

  • Robert T. Knight

  • Tor Endestad

  • Randolph F. Helfrich

Date: 2024

DOI: https://doi.org/10.1038/s41467-023-44571-7

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Decision and response monitoring during working memory are sequentially represented in the human insula

Abstract:

Emerging research supports a role of the insula in human cognition. Here, we used intracranial EEG to investigate the spatiotemporal dynamics in the insula during a verbal working memory (vWM) task. We found robust effects for theta, beta, and high frequency activity (HFA) during probe presentation requiring a decision. Theta band activity showed differential involvement across left and right insulae while sequential HFA modulations were observed along the anteroposterior axis. HFA in anterior insula tracked decision making and subsequent HFA was observed in posterior insula after the behavioral response. Our results provide electrophysiological evidence of engagement of different insula subregions in both decision-making and response monitoring during vWM and expand our knowledge of the role of the insula in complex human behavior.

Authors:

  • Anaïs Llorens

  • Ludovic Bellier

  • Alejandro O. Blenkmann

  • Jugoslav Ivanovic

  • Pål G. Larsson

  • Jack J. Lin

  • Tor Endestad

  • Anne-Kristin Solbakk

  • Robert T. Knight

Date: 2023

DOI: https://doi.org/10.1016/j.isci.2023.107653

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