Frequency domain characterization of the somatosensory steady state response in electroencephalography

Abstract

A continuous somatosensory stimulation evokes a steady state response in the cortex, which can be measured using electroencephalography. We applied mechanical multisine stimulation of the wrist to investigate the properties of the steady state response in the frequency domain. Our results show a response in the contralateral sensorimotor cortex at the stimulated frequencies yet with more power at their even harmonics, indicating substantial nonlinear behavior. The observed cortical response to a mechanical somatosensory stimulation is time invariant and nonlinear, however shows no subharmonics, allowing for the application of a broad range of (non)linear system identification tools.