Attending to our inner world is a fundamental cognitive phenomenon1,2,3, yet its neural underpinnings remain largely unknown. Neuroimaging evidence implicates the default network (DN) and frontoparietal control network (FPCN)4; however, the electrophysiological basis for the interaction between these networks is unclear. Here we recorded intracranial electroencephalogram from DN and FPCN electrodes implanted in individuals undergoing presurgical monitoring for refractory epilepsy. Subjects performed an attention task during which they attended to tones (that is, externally directed attention) or ignored the tones and thought about whatever came to mind (that is, internally directed attention). Given the emerging role of theta band connectivity in attentional processes5,6, we examined the theta power correlation between DN and two subsystems of the FPCN as a function of attention states. We found increased connectivity between DN and FPCNA during internally directed attention compared to externally directed attention, which positively correlated with attention ratings. There was no statistically significant difference between attention states in the connectivity between DN and FPCNB. Our results indicate that enhanced theta band connectivity between the DN and FPCNA is a core electrophysiological mechanism that underlies internally directed attention.
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The data that support the findings of this study are available from the corresponding author upon request.
The custom MATLAB code used to analyse the data that support the findings of this study are available from the corresponding author upon request.
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We appreciate the time put forward by our patients, whose participation was instrumental in this study. We thank A. Jafarpour, A. Breska, J. Zheng, R. Helfrich and V. Piai for discussions, as well as the recording team at each hospital for their help with data collection. This work was supported by the Natural Sciences and Engineering Research Council of Canada and the James S. McDonnell Foundation (to J.W.Y.K.), Research Council of Norway 240389/F20 and Internal Funding from the University of Oslo (to A.-K.S., T.E. and P.G.L.) and NINDS R3721135 (to R.T.K.). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
The authors declare no competing interests.
Peer review information: Primary Handling Editor: Marike Schiffer.
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