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Open Access Highly Accessed Research article

Altered networks in bothersome tinnitus: a functional connectivity study

Harold Burton1*, Andre Wineland2, Mousumi Bhattacharya3, Joyce Nicklaus4, Keith S Garcia5 and Jay F Piccirillo6

Author affiliations

1 Department of Anatomy & Neurobiology and Department of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA

2 Department of Otolaryngology - Head & Neck Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA

3 Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA

4 Department of Otolaryngology - Head & Neck Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA

5 Department of Psychiatry, University of Texas-Southwestern, Austin, Texas, 75390, USA

6 Department of Otolaryngology - Head & Neck Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA

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Citation and License

BMC Neuroscience 2012, 13:3  doi:10.1186/1471-2202-13-3

Published: 4 January 2012

Abstract

Background

The objective was to examine functional connectivity linked to the auditory system in patients with bothersome tinnitus. Activity was low frequency (< 0.1 Hz), spontaneous blood oxygenation level-dependent (BOLD) responses at rest. The question was whether the experience of chronic bothersome tinnitus induced changes in synaptic efficacy between co-activated components. Functional connectivity for seed regions in auditory, visual, attention, and control networks was computed across all 2 mm3 brain volumes in 17 patients with moderate-severe bothersome tinnitus (Tinnitus Handicap Index: average 53.5 ± 3.6 (range 38-76)) and 17 age-matched controls.

Results

In bothersome tinnitus, negative correlations reciprocally characterized functional connectivity between auditory and occipital/visual cortex. Negative correlations indicate that when BOLD response magnitudes increased in auditory or visual cortex they decreased in the linked visual or auditory cortex, suggesting reciprocally phase reversed activity between functionally connected locations in tinnitus. Both groups showed similar connectivity with positive correlations within the auditory network. Connectivity for primary visual cortex in tinnitus included extensive negative correlations in the ventral attention temporoparietal junction and in the inferior frontal gyrus and rostral insula - executive control network components. Rostral insula and inferior frontal gyrus connectivity in tinnitus also showed greater negative correlations in occipital cortex.

Conclusions

These results imply that in bothersome tinnitus there is dissociation between activity in auditory cortex and visual, attention and control networks. The reciprocal negative correlations in connectivity between these networks might be maladaptive or reflect adaptations to reduce phantom noise salience and conflict with attention to non-auditory tasks.

Keywords:
tinnitus; human; MRI; connectivity