EEG frequency tagging
Studies have shown that the periodic repetition or modulation of a stimulus can induce a sustained periodic EEG response at the frequency of stimulation and its harmonics, often referred to as steady-state evoked potential (SS-EP). Unlike event-related potentials (ERPs), which reflect phasic cortical activity triggered by a transient stimulus. SS-EPs reflect sustained cortical activity induced by the entrainment of neuronal populations responding to the stimulus. Our objective is to exploit this "EEG frequency-tagging" technique to explore the cortical activity underlying the perception of sustained pain in humans. This is achieved, for example, using a temperature-controlled CO2 laser stimulator to periodically activate heat-sensitive nociceptors of the skin. Using this technique, we showed that it is possible to isolate cortical activity specifically related to the activation of heat-sensitive C-fiber nociceptors.