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Published on: September 12, 2012
Structural changes of the corpus callosum in tinnitus
Eugen Diesch1, Verena Schummer, Martin Kramer
1Department of Clinical and Cognitive Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University Mannheim, Germany.
Frontiers in Systems Neuroscience
|April 4, 2012
Summary
Tinnitus patients show altered corpus callosum (CC) volumes compared to controls, with differences observed in specific CC regions and sexes. This suggests altered brain connectivity may contribute to tinnitus.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Neuroimaging
Background:
- Tinnitus is associated with structural alterations in brain regions, including the medial Heschl's gyrus (mHG), the primary auditory cortex.
- The corpus callosum (CC) facilitates interhemispheric communication between auditory cortices.
Purpose of the Study:
- To investigate the association between tinnitus and corpus callosum (CC) volume.
- To explore sex-specific differences in CC volume in individuals with tinnitus.
Main Methods:
- Midsagittal cross-sectional area of the CC was analyzed in tinnitus patients and healthy controls.
- The CC was segmented into subregions using established morphometric schemes (Witelson, 1989; Hofer & Frahm, 2006).
- CC size was normalized relative to mHG volume to assess callosal interconnectivity.
Main Results:
- CC posterior midbody was smaller in male tinnitus patients versus controls.
- CC isthmus, anterior midbody, and genou were larger in female tinnitus patients versus controls.
- Normalized CC splenium, isthmus, and genou were larger in both male and female tinnitus patients, indicating increased callosal interconnectivity relative to auditory cortex volume.
Conclusions:
- Tinnitus is associated with altered CC structure and interconnectivity.
- Increased callosal interconnectivity may support a positive feedback loop between bilateral tinnitus generators.
- Findings highlight the role of interhemispheric communication in tinnitus pathophysiology.
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