Establish Which Brain Regions Constitute the Physical Substrate of Consciousness in the Brain: Neural Correlates of Thought, Self and Meta-Awareness
INSTITUTE: University of Wisconsin-Madison / Department of Psychiatry / Center for Sleep and Consciousness
PROJECT LEADER: Giulio Tononi
PROJECT DURATION: 3 years
LAB WEBSITE: Center for Sleep and Consciousness
Much work has been devoted to identifying the neural correlates of consciousness (NCC) for perceptual contents, such as faces, objects, shapes, colors, sounds, and the like. Among the conscious contents that matter the most for defining our view of ourselves and others are those involving thoughts, the self, and our awareness of experience itself (meta-awareness). However, the NCC for thought, self, and meta-awareness are still relatively obscure, partly because investigations of consciousness are often confounded by task performance or focus on cognitive functions, rather than on experience itself.
In this project, we will investigate these NCC by taking advantage of the skills of long-term meditators, who have trained for many years to dissect their experience and modifying it. They are especially adept at achieving states of no thought, no self, and no meta-awareness, so that they can be contrasted with states in which those contents are vividly present. We will thus be able to explore the NCC for thought, self, and meta-awareness by employing high density, 256 electrode electroencephalography (hd-EEG) combined with subjective reports.
Long term meditators will be recruited from the Zen and Tibetan Buddhist traditions and, when feasible, from other Buddhist and Christian traditions. Serial sampling of conscious experience contents will be performed during 30 minutes of spontaneous waking as well as after awakenings from NREM sleep and REM sleep (10-20 awakenings per night) using structured questionnaires. For each sampling time point, subjects will be asked to score on a scale from 1 to 5 the presence of a particular conscious content within the last 30 seconds of their experience. This experience sampling will be probed by a sound (delivered at random intervals every 2-10 minutes) during wakefulness; awakenings will be performed using a tone delivered at random intervals every 20-60 min during NREM and REM sleep. Serial experience sampling will also be performed within the same subjects using tones delivered at random intervals every 2-10 minutes during passive movie watching and, for long-term meditators, during ‘open presence’ meditation practice.
Figure 1. Identifying the NCC for conscious thought. The figure illustrates a local area of midcingulate cortex showing low delta power and higher gamma power when subjects report having experienced a conscious thought during waking, NREM sleep, or REM sleep.
Again using hd-EEG, a similar experimental paradigm, appropriately adapted, will then be employed in meditation-naive subjects to establish whether the NCC obtained in long-term meditators can be confirmed and generalized.
If feasible, we will also use EEG-fMRI to record brain activity while sampling experience contents during spontaneous wakefulness, movie watching, and sleep. These experiments may be performed both in meditation-naive subjects and long-term meditators (20 subjects each).
Finally, whenever feasible, a similar paradigm will be adapted to epileptic subjects undergoing clinical presurgical mapping using intracranial recordings.
Broader Impact:
Among the contents of consciousness, those for thought, self, and meta-awareness (the ability to reflect on one’s experience) are especially important. A better scientific understanding of the neural correlates of thought, self, and meta-awareness is therefore key to any efforts to change and expand our experience of ourselves and the world.
Publications:
Baird B, et al. “Lucid dreaming occurs in activated REM sleep, not a mixture of sleep and wakefulness”. SLEEP (in press).
Baird, B et al. "Two-Way Communication in Lucid REM Sleep Dreaming", Trends in Cognitive Science, 25.6 (2021): 427-428.
Baird B, Kalkach Aparicio M, Alauddin T, Riedner B, Boly M, Tononi G “Episodic thought distinguishes spontaneous cognition in waking from REM and NREM sleep”. Consciousness and Cognition, 97 (2021): 103247.
Baird, Benjamin, et al. "Frequent Lucid Dreaming Associated with Increased Functional Connectivity between Frontopolar Cortex and Temporoparietal Association Areas." Scientific Reports 8.1 (2018): 17798.
Perogamvros, Lampros, et al. "The Phenomenal Contents and Neural Correlates of Spontaneous Thoughts across Wakefulness, NREM Sleep, and Rem Sleep." Journal of Cognitive Neuroscience 0.0 (2017): 1-12.