Pereira Michael, Megevand Pierre, Tan Mi Xue, Chang Wenwen, Wang Shuo, Rezai Ali, Seeck Margitta, Corniola Marco, Momjian Shahan, Bernasconi Fosco, Blanke Olaf, Faivre Nathan (2021), Evidence accumulation relates to perceptual consciousness and monitoring, in Nature Communications
, 12(1), 3261-3261.
One of the most fascinating neuroscientific question is to explain how neuronal activity relates to thoughts and thus to consciousness. The scientific approach to this question is to compare conscious and unconscious brain activity in order to find the so-called neural correlates of consciousness (NCC). During the last 30 years however, only very few researchers have looked into subcortical structures despite their putative role in consciousness. In the following research project, I propose to study for the first time the contribution of subcortical brain structures to human consciousness at the single neuron level (work package 1), and assess their causal influence on behaviour and scalp electrophysiology (work package 2). In work-package 1 (WP1), I will rely on the unique opportunity to do microelectrode recordings (MER) subcortical single neuron activity (SUA) and local field potentials (LFP) in awake humans during deep brain stimulation (DBS) surgery for Parkinson’s disease and essential tremor. I expect that neural activity in the subthalamic nucleus (STN) and in the ventralis caudalis (Vc) nucleus in the thalamus will reflect subjective experience associated with the detection of a weak vibrotactile stimulation and that these differences will occur both at the population level (indexed by local field potentials) and at the single neuron level. This hypothesis is supported by two pilot recordings. In work-package 2 (WP2), I will compare electroencephalography (EEG) and subjective reports of perception while DBS is ON vs. OFF (further referred to as EEG-DBS) in order to assess the causal influence of subcortical structures on conscious perception, as well as the importance of subcortico-cortical loops for consciousness. In both work-packages, I will use a computational model to disentangle whether neural activity reflects the processing of perceptual evidence or rather the encoding of a decision threshold. The project is multicentric; WP1 will be carried out with the Rockefeller Neuroscience Institute at the West Virginia University Hospital in Morgantown, US and WP2 will be carried out at the Centre Hospitalier Universitaire (CHU) hospital in Grenoble, France. Collectively, WP1 (MER-DBS) and WP2 (EEG-DBS) will shed new lights on the subcortical origins of human consciousness, and inform several influential theoretical frameworks (Tononi et al., 2016; Dehaene & Changeux, 2011).