FMRI mapping of the somatosensory cortex with vibratory stimuli: Is there a dependency on stimulus frequency?

Abstract

Vibratory stimuli on the skin are mediated by two major receptors: Meissner corpuscles and Pacinian corpuscles. These receptors differ in properties such as density distribution, receptive field size, frequency sensitivity and depth of location. The cortical response to stimulation of these corpuscles can be tested by taking advantage of the differences in frequency discrimination of the receptors. Meissner corpuscles are most sensitive to frequencies around 10–50 Hz (flutter), while Pacinian corpuscles are most sensitive to high frequency (100–300 Hz) vibration. This study compared the neuronal responses (hemodynamic response) generated from vibratory stimuli of 35 Hz and 150 Hz with functional MRI. Group functional activation maps showed differences in the activation pattern for the two stimulus frequencies.