Does Stimulus-Preceding Negativity Reflect Predictions in a Somatosensory Roving Paradigm?

The mismatch negativity (MMN) has since decades become one of the most prominent phenomena in cognitive neuroscience, recognized as a brain response indexing automatic change detection. While substantial work has characterized poststimulus mismatch responses (MMRs), comparatively little is known about how prior information is represented before stimulus onset. Thirty-four healthy human volunteers (12 females) underwent a somatosensory roving paradigm with electroencephalography to investigate whether anticipatory brain activity reflects stimulus history accumulation. Poststimulus analyses revealed canonical somatosensory MMRs, corresponding to a modulation of the N140 component (MMN), source localized in the secondary somatosensory cortex, and a P300 MMR. Both were parametrically modulated by train length, with opposing direction for standard and deviant trials, decreasing over the course of the experiment. Prestimulus analyses revealed a stimulus-preceding negativity (SPN) that systematically varied as a function of stimulus history; longer trains of stimulus repetitions were associated with reduced anticipatory negativity. The SPN did not vary throughout the experiment, but its relationship with poststimulus responses evolved, showing an initially negative correlation with the N140 that diminished over time and an opposite pattern for the P300. Source reconstruction localized the SPN to a network involving inferior frontal, frontopolar, and somatosensory cortices, suggesting a possible role in top-down gain modulation of upcoming sensory stimuli. These findings indicate that learning of statistical regularities is not only observable in the poststimulus phase following violation of statistical regularities (i.e., prediction error signals), but also in neural activity preceding sensory inputs, thereby providing new avenues for investigating endogenous predictive processes.