Content-Free Awareness: EEG-fcMRI Correlates of Consciousness as Such in an Expert Meditator

Ulf Winter; Pierre LeVan; Tilmann L Borghardt; Burak Akin; Marc Wittmann; Yeshe Leyens; Stefan Schmidt

doi:10.3389/fpsyg.2019.03064

Content-Free Awareness: EEG-fcMRI Correlates of Consciousness as Such in an Expert Meditator

Front Psychol. 2020 Feb 18:10:3064. doi: 10.3389/fpsyg.2019.03064. eCollection 2019.

Authors

Ulf Winter¹, Pierre LeVan^{2

3}, Tilmann L Borghardt⁴, Burak Akin^{2

5}, Marc Wittmann⁶, Yeshe Leyens¹, Stefan Schmidt¹

Affiliations

¹ Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
² Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
³ Departments of Radiology and Paediatrics, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
⁴ The Ekayana Institute, Lenzkirch, Germany.
⁵ Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
⁶ Institute for Frontier Areas of Psychology and Mental Health, Freiburg im Breisgau, Germany.

Abstract

The minimal neural correlate of the conscious state, regardless of the neural activity correlated with the ever-changing contents of experience, has still not been identified. Different attempts have been made, mainly by comparing the normal waking state to seemingly unconscious states, such as deep sleep or general anesthesia. A more direct approach would be the neuroscientific investigation of conscious states that are experienced as free of any specific phenomenal content. Here we present serendipitous data on content-free awareness (CFA) during an EEG-fMRI assessment reported by an extraordinarily qualified meditator with over 50,000 h of practice. We focused on two specific cortical networks related to external and internal awareness, i.e., the dorsal attention network (DAN) and the default mode network (DMN), to explore the neural correlates of this experience. The combination of high-resolution EEG and ultrafast fMRI enabled us to analyze the dynamic aspects of fMRI connectivity informed by EEG power analysis. The neural correlates of CFA were characterized by a sharp decrease in alpha power and an increase in theta power as well as increases in functional connectivity in the DAN and decreases in the posterior DMN. We interpret these findings as correlates of a top-down-initiated attentional state excluding external sensory stimuli and internal mentation from conscious experience. We conclude that the investigation of states of CFA could provide valuable input for new methodological and conceptual approaches in the search for the minimal neural correlate of consciousness.

Keywords: EEG-fMRI; consciousness as such; content-free awareness (CFA); default-mode network (DMN); disconnected consciousness; dorsal attention network (DAN); meditation; neural correlate of consciousness (NCC).