In Phase 2 of the project will comprise of an EEG-registration with the different types of electrodes in healthy volunteers. For each volunteer the EEG-recording with dry electrodes will be compared to the EEG-recordings with conventionally used wet electrodes (bridge and cup electrodes). In addition each volunteer will undergo a somato-sensory evoked potential (SSEP) measurement with different types of electrodes. Analogously to the EEG-registrations, for each volunteer the SSEP measurement with the dry electrodes will be compared to the SSEP measurement with conventionally used wet electrodes (bridge and cup electrodes). Each EEG-registration will take between 5 and 10 minutes.