A multichannel electrophysiological approach to noninvasively and precisely record human spinal cord activity
Birgit Nierula, Tilman Stephani, Emma Bailey, Merve Kaptan, Lisa-Marie G. Pohle, Ulrike Horn, André Mouraux, Burkhard Maeß, Arno Villringer, Gabriel Curio, Vadim V. Nikulin, Falk Eippert
Abstract
The spinal cord is of fundamental importance for integrative processing in brain-body communication, yet routine noninvasive recordings in humans are hindered by vast methodological challenges. Here, we overcome these challenges by developing an easy-to-use electrophysiological approach based on high-density multichannel spinal recordings combined with multivariate spatial-filtering analyses. These advances enable a spatiotemporal characterization of spinal cord responses and demonstrate a sensitivity that permits assessing even single-trial responses. To furthermore enable the study of integrative processing along the neural processing hierarchy in somatosensation, we expand this approach by simultaneous peripheral, spinal, and cortical recordings and provide direct evidence that bottom-up integrative processing occurs already within the spinal cord and thus after the first synaptic relay in the central nervous system. Finally, we demonstrate the versatility of this approach by providing noninvasive recordings of nociceptive spinal cord responses during heat-pain stimulation. Beyond establishing a new window on human spinal cord function at millisecond timescale, this work provides the foundation to study brain-body communication in its entirety in health and disease.