Neural Correlates of Conscious Perception Investigated with Simultaneous Intracranial and High-Density Scalp Recordings in Humans and Report/No-Report Paradigms
INSTITUTION: University of Milan, Italy
PROJECT LEADERS:
PI: Marcello Massimini, MD PhD; Andrea Pigorini PhD; Exequiel Mikulan PhD; Simoe Russo MD
PROJECT DURATION: 3 years
A key problem in the science of consciousness is that most studies about conscious perception are confounded by accessory activations in the frontal lobe that are associated to task relevance and reporting, rather than to experience per se.
Using no-report tasks, it has been shown that responses to somatosensory stimulations can be decomposed according to their time course in phasic and tonic components (Avanzini, PNAS), each possessing a specific somatotopic and latency organization, with tonicity proposed as a neural correlate of conscious perception. This has been recently demonstrated by showing the anatomo-functional overlap between tonicity maps with the lesional mapping of post-stroke patients suffering from tactile extinction (Del Vecchio Brain 2021).
Here, employing combined intracranial and extracranial (256 channels) recordings of neural responses to sensory stimulation in no-report conditions and source modelling techniques, we were first able to capture the tonic and phasic responses directly from the scalp. Next, we aimed to develop an algorithm to predict the intracranial responses by using the EEG data, as this would represent a major technical advance that would not only show that it is possible to observe scalp level reflections of high-frequency intracranial responses, but it would also open the possibility of the evaluation of the tonic/phasic components in new populations. Specifically, we aim at explicitly connecting the Perceptual Awareness Negativity (PAN) (Dembski et al., 2021), a candidate EEG of sensory consciousness to the tonic response, its putative neuronal counterpart. Preliminary analysis showed that using a state-of-the-art Receptive Field estimation algorithm (Domoulin & Wandell, Neuroimage, 2007), we were indeed capable of predicting the intracranial tonic response by using scalp EEG data only.
Broader Impact:
A key emerging problem in the science of consciousness is that most studies about conscious perception are confounded by accessory activations in the frontal lobe that are associated to task relevance, executive functions and reporting, rather than to experience per se. Resolving this problem amounts to distinguishing between the neural correlates of doing and the neural correlates of being and it of outmost importance to arbitrate between different accounts of experience.
Publications:
Avanzini, P., Abdollahi, R.O., Sartori, I., Caruana, F., Pelliccia, V., Casaceli, G., Mai, R., Lo Russo, G., Rizzolatti, G., and Orban, G.A. (2016). Four-dimensional maps of the human somatosensory system. Proc. Natl. Acad. Sci. U. S. A. 113, E1936-1943. https://doi.org/10.1073/pnas.1601889113.
Del Vecchio, M., Fossataro, C., Zauli, F.M., Sartori, I., Pigorini, A., d’Orio, P., Abarrategui, B., Russo, S., Mikulan, E.P., Caruana, F., et al. (2021). Tonic somatosensory responses and deficits of tactile awareness converge in the parietal operculum. Brain 144, 3779–3787. https://doi.org/10.1093/brain/awab384.
Dembski, C., Koch, C., and Pitts, M. (2021). Perceptual awareness negativity: a physiological correlate of sensory consciousness. Trends Cogn. Sci. 25, 660–670. https://doi.org/10.1016/j.tics.2021.05.009.