Pub Med Gov Brain Res. 2021 Jan 7;147277.
Somayeh Shahsavarani, Sara A. Schmidt, Rafay A. Khan Yihsin Tai, Fatima T. Husain
In the study, innovative music-rest interleaved fMRI paradigm was to investigate the neural correlates of tinnitus distress.
Background
Tinnitus where individuals perceive sounds in the absence of an external source is poorly understood. Although the great majority of individuals habituate to chronic tinnitus and report symptoms, a minority report debilitating distress and annoyance. Prior research suggests that a diverse set of brain regions, including the attention, the salience, and the limbic networks, play key roles in mediating both the perception of tinnitus and its impact on the individual. Salience is the way researchers understand what information will most likely capture one's attention in a given situation and have the greatest influence on one's cognitions about the stimuli. The limbic system is thought to be an important element in the body's response to stress, being highly connected to the endocrine and autonomic nervous systems.
However, evidence of the degree and extent of their involvement has been inconsistent. The conventional resting state fMRI was minimally modified by interleaving it with segments of jazz music.
Results
The functional connectivity between a set of brain regions-including cerebellum, precuneus, superior/middle frontal gyrus, and primary visual cortex-and seeds in the dorsal attention network, the salience network, and the amygdala, were effective in fractionating the tinnitus patients into two subgroups, characterized by the severity of tinnitus-related distress. Further, the findings revealed cross-modal modulation of the attention and salience networks during the music segments. On average, the more bothersome the reported tinnitus, the stronger was the exhibited inter-network functional connectivity.
Conclusion
This study substantiates the essential role of the attention, salience, and limbic networks in tinnitus habituation, and suggests modulation of the attention and salience networks across the auditory and visual modalities as a possible compensatory mechanism for bothersome tinnitus.