Haab L, Scheerer M, Ruckert J, Hannemann R, Strauss D J
Systems Neuroscience Neurotechnology Unit, Neurocenter, Saarland University Hospital, Homburg/Saar, Germany.
Annu Int Conf IEEE Eng Med Biol Soc. 2012;2012:5578-81. doi: 10.1109/EMBC.2012.6347258.
The pathogenesis of tinnitus involves multiple hierarchical levels of auditory processing and appraisal of sensory saliency. Early tinnitus onset is most likely attributed to homeostatic plasticity in the periphery, while the chronification and decompensation are tightly linked to brain areas for the allocation of attentional resources, such as e.g., the thalamocortical feedback loops and the limbic system. Increased spontaneous firing after sensory deafferentation might be sufficient to generate a phantom perception, yet the question why not every peripheral hearing loss automatically elicits a tinnitus sensation is still to be addressed. Utilizing quantitative modeling of multiple hierarchical levels in the auditory pathway, we demonstrate the effects of lateral inhibition on increased spontaneous firing and the resulting elevation of firing regularity and synchronization of neural activity. The presented therapeutical approach is based on the idea of disrupting the heightened regularity of the neural population response in the tinnitus frequency range. This neural activity regularity depends on lateral dispersion of common noise and thus is susceptible for edge effects and might be influenced by a change in neural activity in bordering frequency ranges by fitted acoustical stimulation. We propose the use of patient specifically adapted tailor-made notched acoustic stimulation, utilizing modeling results for the optimal adjustment of the stimulation frequencies to archive a therapeutical edge-effect.
耳鸣的发病机制涉及听觉处理和感觉显著性评估的多个层次。耳鸣早期发作最可能归因于外周的稳态可塑性，而慢性化和失代偿则与用于分配注意力资源的脑区紧密相关，例如丘脑皮质反馈回路和边缘系统。感觉传入神经切断后自发放电增加可能足以产生幻听，但为何并非所有外周性听力损失都会自动引发耳鸣感觉这一问题仍有待解决。通过对听觉通路中多个层次进行定量建模，我们展示了侧向抑制对自发放电增加以及由此导致的神经活动放电规律性和同步性升高的影响。所提出的治疗方法基于破坏耳鸣频率范围内神经群体反应增强的规律性这一理念。这种神经活动规律性取决于共同噪声的侧向扩散，因此易受边缘效应影响，并且可能会受到通过拟合声学刺激使相邻频率范围内神经活动变化的影响。我们建议使用针对患者专门定制的带凹口声学刺激，利用建模结果对刺激频率进行优化调整，以获得治疗性边缘效应。
