Image via WikipediaMicroTransponder, a neuroscience-based medical device company, was founded by UT Dallas Ph.D. candidate Will Rosellini and sponsored by the school’s Institute for Innovation and Entrepreneurship. MicroTransponder is developing a less invasive wireless medical device to stimulate the vagus nerve. The UT Dallas/MicroTransponder team also is studying how best to optimize the paired therapy for tinnitus patients.
Past research has shown
that the severity of chronic pain and tinnitus is tied to the degree of
plasticity in the brain’s cortex. A previous study showed that
repeatedly pairing sensory stimuli with electrical stimulation of a
brain structure called nucleus basalis generates powerful and
long-lasting changes in cortical organization. Since the vagus nerve is
easier to access for clinical use, and is known to trigger the release
of molecules in the brain that promote neural changes, follow-up studies
were performed on the vagus nerve.
For the VNS study, the
research team used a “gap detection model” to document tinnitus in rats
that were exposed to loud noise for one hour while under anesthesia.
Each of the noise-exposed rats used in this study exhibited a
significant impairment in the ability to detect a quiet gap in a tone
near their tinnitus frequency, but exhibited no impairment when the gap
was placed in a higher or lower tone.
“Previous research showed
that a frequency-specific impairment in gap detection is a likely sign
that noise-exposed rats experience a mid-frequency tinnitus ‘ringing’
that fills the silent gaps,” Kilgard said. “Though it isn’t possible to
evaluate the subjective experience of rats, this gap impairment has been
taken as an indicator of tinnitus.”
When the rats were exposed to VNS paired with sounds, the gap impairment was eliminated – indicating that the tinnitus was gone.
Stimulating the Vagus nerve is also being used for treatment resistant major depression and epilepsy.