ScienceDaily (June 23, 2010) — About 40 million people in the U.S. today suffer from tinnitus, an irritating and sometimes debilitating auditory disorder in which a person "hears" sounds, such as ringing, that don't actually exist. There isn't a cure for what has long been a mysterious ailment, but new research suggests there may, someday, be a way to alleviate the sensation of this sound, says a neuroscientist from Georgetown University Medical Center (GUMC)
In a Perspective piece in the June 24 issue of Neuron, Josef P. Rauschecker, PhD, says that tinnitus should be thought of as a disorder akin to the "phantom pain" felt in an amputated limb.
Tinnitus starts with damage to hair cells in the cochlea of the inner ear. This damage forces neurons in the brain's auditory areas, which normally receive input from that part of the cochlea, to become overactive to fill in the missing sound, he says. That extra, unreal noise is normally inhibited -- or tuned out -- by a corrective feedback loop from the brain's limbic system to the thalamus, where all sensory information is regulated, before it reaches the cerebral cortex, where a person becomes conscious of the senses. But that doesn't happen in tinnitus patients due to compromised brain structures in the limbic system.
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