Thalamic bursts modulate cortical synchrony locally to switch between states of global functional connectivity in a cognitive task

Abstract

Performing a cognitive task requires going through a sequence of functionally diverse stages. Although it is typically assumed that these stages are characterized by distinct states of cortical synchrony that are triggered by sub-cortical events, little reported evidence supports this hypothesis. To test this hypothesis, we first identified cognitive stages in single-trial MEG data of an associative recognition task, showing with a novel method that each stage begins with local modulations of synchrony followed by a state of directed functional connectivity. Second, we developed the first whole-brain model that can simulate cortical synchrony throughout a task. The model suggests that the observed synchrony is caused by thalamocortical bursts at the onset of each stage, targeted at cortical synapses and interacting with the structural anatomical connectivity. These findings confirm that cognitive stages are defined by distinct states of cortical synchrony and explains the network-level mechanisms necessary for reaching stage-dependent synchrony states.

Localizing memory retrieval in time and space

“…To link discovered stages to specific brain regions, the method has recently been extended to MEG (Anderson et al, 2018;Portoles, Blesa, van Vugt, Cao, & Borst, 2022). While MEG has a higher sensitivity to tangential sources as compared to EEG, it is not sensitive to radial sources (Hansen, Kringelbach, & Salmelin, 2010).…”

“…This would mean that the HsMM-MVPA analysis method should be further adjusted when applied to MEG, specifically. For example, in a recent study, Portoles, Blesa, van Vugt, Cao, & Borst (2022) applied HsMM-MVPA to source reconstructed data rather than MCCA components from the sensor data used in our study. This highlights an interesting direction for future research, however, this approach also presents additional constraints such as assumptions underlying the particular source solution.…”