Stage 1: Preliminary Research
A multi-disciplinary project involving neural, electrical, and basic biomedical and mechanical engineering. Stage one consisted of researching and constructing a paradigm exploring the somatosensory response to vibration stimuli on the subjects upper extremities. Research of prior experiments concluded that vibration intensity was subjectively the greatest when the stimuli was localized on the subjects median nerve. Research also showed that the subjects ability to localize stimuli was greatest when applied near joints, such as the wrist and elbow.
Pacinian corpuscles, which are nerve endings in the skin responsible for sensitivity to vibration and pressure, are most sensative to stimuli presented at approximately 250Hz. Meissner corpuscles are nerve endings in the skin responsible for sensitivity to light touch, and have their highest sensitivity when sensing vibrations between 10-15Hz.
Stage 2: Experiment
Due to sampling limitations on the EEG, the lab opted to providing a 21Hz, modulated by 128Hz, vibration stimuli on the subjects' wrists. Frequency analysis of the collected EEG data showed peaks in the beta waves spectrum, specifically at 21Hz, in channels located near the subject's somatosensory cortex. Analysis showed the amplitude of the transform to be greater in the contralateral hemisphere from the wrist which was presented with the stimuli.