Cross-Modal Interactions of Auditory and Somatic Inputs in the Brainstem and Midbrain and Their Imbalance in Tinnitus and Deafness
Cross-Modal Interactions of Auditory and Somatic Inputs in the Brainstem and Midbrain and Their Imbalance in Tinnitus and Deafness
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DOI：
10.1044/1059-0889(2008/07-0045
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发表时间：
2008-12-01
影响因子：
1.8
通讯作者：
Shore, S. E.
中科院分区：
文献类型：
--
作者：
Dehmel, S.;Cui, Y. L.;Shore, S. E.
目的：综述躯体感觉对正常脑干和中脑听觉加工影响的解剖学和功能基础。然后探讨了听觉和体感系统之间的相互作用如何通过耳聋进行修改，并讨论了它们对耳鸣的影响。方法：采用文献复习、尿路示踪、免疫组化、体内电生理记录等方法。结果：躯体感觉输入源起于背根神经节和三叉神经节，经二级核直接或间接传递至耳蜗腹侧核、耳蜗背核（DCN）和下丘。谷氨酸能体感觉传入神经可以通过其末端存在的水泡状谷氨酸转运蛋白类型与听神经输入神经分离。体感觉输入的电刺激导致兴奋和抑制的复杂组合，并改变对声刺激的反应速率和时间。耳聋增加了那些接受兴奋性体感输入的神经元的自发率，并导致DCN神经元对三叉神经刺激的更大敏感性。结论：听觉-体感双峰整合在一级听核中已经存在。由体感输入引起的兴奋和抑制的平衡在耳聋后发生改变。当听觉输入减少时，体感觉对听觉神经元的影响增加可能是由于交叉模态再神经支配或突触强度增加，并可能有助于躯体耳鸣的机制。
Purpose: This review outlines the anatomical and functional bases of somatosensory influences on auditory processing in the normal brainstem and midbrain. It then explores how interactions between the auditory and somatosensory system are modified through deafness, and their impact on tinnitus is discussed.Method: Literature review, tract tracing, immunohistochemistry, and in vivo electrophysiological recordings were used.Results: Somatosensory input originates in the dorsal root ganglia and trigeminal ganglia, and is transmitted directly and indirectly through 2nd-order nuclei to the ventral cochlear nucleus, dorsal cochlear nucleus (DCN), and inferior colliculus. The glutamatergic somatosensory afferents can be segregated from auditory nerve inputs by the type of vesicular glutamate transporters present in their terminals. Electrical stimulation of the somatosensory input results in a complex combination of excitation and inhibition, and alters the rate and timing of responses to acoustic stimulation. Deafness increases the spontaneous rates of those neurons that receive excitatory somatosensory input and results in a greater sensitivity of DCN neurons to trigeminal stimulation.Conclusions: Auditory-somatosensory bimodal integration is already present in 1st-order auditory nuclei. The balance of excitation and inhibition elicited by somatosensory input is altered following deafness. The increase in somatosensory influence on auditory neurons when their auditory input is diminished could be due to cross-modal reinnervation or increased synaptic strength, and may contribute to mechanisms underlying somatic tinnitus.