Dallas — University of Texas – Dallas (UT Dallas) neuroscientists are examining whether multiple areas of the brain are responsible for causing tinnitus. The research may one day enable new medical interventions.

Tres Thompson, PhD, associate professor in UT Dallas’ School of Behavioral and Brain Sciences, (pictured, right) found that exposure to loud noises induces plasticity in the hippocampus, a section of the brain not primarily associated with hearing, but known for learning-related plasticity. This “neuroplasticity,” or changes in the function of the brain in reaction to experiences, could open the door to long-term tinnitus, he said in the press statement.

A 3-year, $135,000 grant from the American Tinnitus Association supports this work in Thompson’s lab. The next stage of research will focus on drug treatments aimed at reducing or reversing plasticity. Thompson wants to test whether certain drugs targeting plasticity mechanisms might inhibit or change plasticity, protecting against tinnitus.

The hippocampus neurons of laboratory rats exhibited plasticity within 15 minutes of exposure to intense noise that can induce tinnitus in humans and rats.

Instead of mapping the “normal” world, the neurons conveyed an altered picture of the world around the rats, one that rapidly changed.

The electrical signaling in the brain continued to change for another 12 hours after noise exposure. Electrical monitoring of the rats’ brain cells indicated plasticity started in the hippocampus long before outward signs of tinnitus, such as ringing in the ears, showed up.

Major remapping of neurons could help explain why people exposed to extremely loud or continual noise experience lingering hearing disruption, Thompson said. Researchers previously concentrated only on the auditory portions of the brain involved in tinnitus.

Thompson, whose research focuses primarily on aging and memory, began looking at the role of the hippocampus in tinnitus while investigating how brain cells change as they learn.

“It turns out that tinnitus is, in effect, a learning event,” he said.

SOURCE: University of Texas – Dallas