Work

Simultaneous recordings link intracranial and scalp correlates of somatosensory awareness in humans

Year: 2026

Type: preprint

Abstract: The electrophysiological events underlying the conscious perception of touch in humans remain elusive. Scalp-EEG studies have identified a negative deflection peaking 120-200 ms after stimulus onset, known as the N140. This component, recently reinterpreted as the somatosensory awareness negativity (N140/SAN), has been proposed as a putative marker of tactile awareness, but its underlying neuronal dynamics are still unknown. Intracranial studies have shown that responses to median nerve stimulation include, after an initial phasic activation mainly localized to primary somatosensory cortices, a predominantly insulo-opercular tonic broadband high-frequency activity (BHA; 50-150 Hz) that has been linked to tactile awareness. Yet these scalp and intracranial signatures have never been directly linked. Using simultaneous high-density scalp EEG and intracranial EEG recordings, we show that the N140/SAN is the scalp manifestation of the insulo-opercular local field potential that follows the BHA response to stimulation. By bridging invasive and non-invasive recordings our results identify the neural origins of the N140/SAN and connect scalp and intracranial correlates of somatosensory awareness. Significance statement Understanding the neural correlates of somatosensory perception remains a central challenge in neuroscience. This study bridges macroscale and mesoscale perspectives by linking the scalp N140/SAN—a putative marker of somatosensory awareness—to intracranial local field potentials (LFPs) and broadband high-frequency activity (BHA, 50-150 Hz) in the parietal operculum and posterior insula. These findings reveal the generators of the N140/SAN and link scalp and intracranial accounts of somatosensory awareness.

Source: bioRxiv (Cold Spring Harbor Laboratory)

DOI: 10.64898/2026.10.03.756393