Somatosensory high frequency oscillations across the human central nervous system
Sensory information processing in the central nervous system (CNS) requires both post-synaptic responses and spiking activity, with human electroencephalography (EEG) research largely focused on the former. However, EEG data also contain high-frequency oscillations (HFOs), which have been linked to cortical spike bursts in animal models, thus providing a non-invasive macroscopic marker of population spiking in humans. Here, we go beyond cortical processing and demonstrate that it is possible to simultaneously record HFOs to somatosensory stimulation across the entire human CNS - from spinal cord over subcortical to cortical processing stages. Using multivariate spatial filtering approaches in two independent datasets, we identify replicable and generalizable HFOs across the CNS and obtain a detailed characterization of these signals at each processing level. Finally, we provide evidence at the between- and within-individual level that low and high frequency electrophysiological responses represent at least partly independent information across the CNS. Taken together, our approach offers the first evidence that it is possible to detect and characterise HFOs simultaneously across the CNS, providing a unique non-invasive and multi-level window into human neurophysiology in health and disease.