Ghazaleh Naghmeh, Zwaag Wietske van der, Clarke Stephanie, Ville Dimitri Van De, Maire Raphael, Saenz Melissa
Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland.
Brain Topogr. 2017 Sep;30(5):685-697. doi: 10.1007/s10548-017-0547-1. Epub 2017 Feb 6.
Animal models of hearing loss and tinnitus observe pathological neural activity in the tonotopic frequency maps of the primary auditory cortex. Here, we applied ultra high-field fMRI at 7 T to test whether human patients with unilateral hearing loss and tinnitus also show altered functional activity in the primary auditory cortex. The high spatial resolution afforded by 7 T imaging allowed tonotopic mapping of primary auditory cortex on an individual subject basis. Eleven patients with unilateral hearing loss and tinnitus were compared to normal-hearing controls. Patients showed an over-representation and hyperactivity in a region of the cortical map corresponding to low frequencies sounds, irrespective of the hearing loss and tinnitus range, which in most cases affected higher frequencies. This finding of hyperactivity in low frequency map regions, irrespective of hearing loss range, is consistent with some previous studies in animal models and corroborates a previous study of human tinnitus. Thus these findings contribute to accumulating evidence that gross cortical tonotopic map reorganization is not a causal factor of tinnitus.
听力损失和耳鸣的动物模型显示，在初级听觉皮层的音频定位频率图中存在病理性神经活动。在此，我们应用7T超高场功能磁共振成像（fMRI）来测试单侧听力损失和耳鸣的人类患者在初级听觉皮层的功能活动是否也发生改变。7T成像提供的高空间分辨率能够在个体受试者基础上对初级听觉皮层进行音频定位映射。将11名单侧听力损失和耳鸣患者与听力正常的对照组进行比较。患者在皮层图中对应低频声音的区域表现出过度表征和活动亢进，无论听力损失和耳鸣范围如何，而在大多数情况下，听力损失和耳鸣影响的是高频区域。低频图区域的这种活动亢进发现，无论听力损失范围如何，都与之前一些动物模型研究一致，并证实了之前一项关于人类耳鸣的研究。因此，这些发现有助于积累证据，表明总体皮层音频定位图重组不是耳鸣的因果因素。
