An MRI and MEG Compatible Device for the Study of Somatosensory Information Processing.

Abstract

In previous publications we have reported methods for applying multi-site vibratory stimuli to the fingertips.  Typically, this involves the use of multiple, individual vibrotactile stimulator and limitations of such an arrangement include difficulty with both positioning the stimuli as well as ensuring that stimuli are delivered in a synchronized and deliberate manner. The device that we reported is a significant improvement on multiple independent stimulators (Holden et al, 2011), and due to both the success of that stimulator and the consequent need to validate a number of findings that have been made with both that device and the precursor of that device (Tannan et al, 2007a), we designed and fabricated a four-site stimulator that could be used in MRI and MEG compatible environments. The device can stimulate four independent skin sites and is primarily designed for stimulating the digit tips. The device is similar to the previously reported device in that it is portable and is ergonomically suited for delivering stimuli to the finger tips, but it has the advantage of being MRI and MEG compatible. However, the fundamental mechanisms of the device are significantly different from the device that we recently reported since the device is piezo-based rather than VCA based. The device was tested in both MEG and MRI environments and demonstrated that no detectable signal (or noise) was introduced by the stimulator in those environments.  To demonstrate the reliability of the device for delivering tactile stimulation in a magnetic field, tactile stimuli were presented in an MRI to a single individual. The study produced results that were consistent with prior studies that produced activation of cortical ensembles.