The role of the parabrachial nucleus in the natural history of tinnitus and its implications.

The final common pathway in severe tinnitus is modified to include the parabrachial nucleus, which has been identified by c-fos immunocytochemistry as an active, non-auditory site. The parabrachial nucleus acts in conjunction with the amygdala and insula (part of the medial temporal lobe system) to produce a somatic emotional sense that can result in a "bad" feeling. The activation of the final common pathway is rapid, suggesting that early treatment is prudent to prevent neuroplastic changes that would likely lessen affect.