Research indicates that at least some cases of tinnitus are associated with particular activity in the brain. On the left is a representative image of the activity in a brain experiencing left-sided tinnitus.  In the middle is a representation of bilateral tinnitus and on the right is the same brain without tinnitus.  Although small, these differences in activity may provide clues as to how tinnitus 'works' and possible treatments.  These images were derived from MRI, fMRI and PET scans and are for illustrative purposes only.