Neurological Surgery, University of California at San Francisco, San Francisco, California, USA.
Neurosurgery. 2012 Feb;70(2):398-405; discussion 405-6. doi: 10.1227/NEU.0b013e3182320ab5.
Tinnitus is predominantly viewed as the consequence of dysfunctional hyperactivity, plastic change, or synchronized oscillations in the central auditory system. An alternative to the current auditory-centric view of auditory phantom perception is the basal ganglia-centric view. Recent electrical stimulation experiments in area LC, a locus of the caudate nucleus positioned at its anterior body, has shown loudness modulation of existing tinnitus percepts.
To demonstrate that auditory phantoms are gated by the dorsal striatum.
Electrical stimulation in area LC via a deep brain stimulation lead was performed in 6 interactive adult subjects (3 with and 3 without chronic tinnitus) undergoing surgery to treat movement disorders. Tinnitus loudness was rated on a 0 to 10 scale, sound quality was described, and localization was referenced to 1 or both ears.
Short-term area LC stimulation triggered new phantom tones, clicks, and frequency modulated sounds in 5 subjects and altered sound quality of an existing tinnitus percept in 1 subject. The results of this study indicate that perceptual awareness of auditory phantoms is contingent on satisfying a permission condition controlled by the dorsal striatum. Potential auditory phantoms are not automatically gated to reach perceptual awareness. A phantom percept gate control model is proposed.
Neuromodulation of area LC can trigger temporary gate dysfunction and reversibly release new phantoms for conscious awareness. Restoration of restrictive dorsal striatal gate function to treat problematic phantom percepts may be realized by adopting long-term area LC neuromodulation and choosing optimal stimulation parameters.
耳鸣主要被视为中枢听觉系统功能障碍、可塑性改变或同步振荡的结果。听觉中枢观点认为，听觉幻觉感知的替代方案是基底神经节中枢观点。最近在 LC 区（尾状核的一个位置，位于其前体）进行的电刺激实验表明，现有的耳鸣知觉响度可调制。
证明听觉幻觉是由背侧纹状体控制的。
通过深部脑刺激导联在 6 名互动成年受试者（3 名有慢性耳鸣和 3 名无慢性耳鸣）中进行 LC 区的电刺激，这些受试者正在接受治疗运动障碍的手术。耳鸣响度在 0 到 10 的范围内进行评分，声音质量进行描述，并参照 1 只或 2 只耳朵进行定位。
在 5 名受试者中，短期 LC 区刺激触发了新的幻音、喀哒声和调频声音，在 1 名受试者中改变了现有耳鸣知觉的声音质量。本研究的结果表明，听觉幻觉的知觉意识取决于满足由背侧纹状体控制的许可条件。潜在的听觉幻觉不会自动被门控以达到知觉意识。提出了一个幻觉感知门控模型。
LC 区的神经调节可以触发暂时的门控功能障碍，并可逆地释放新的幻影，以实现意识。通过采用长期 LC 区神经调节和选择最佳刺激参数，可能实现对有问题的幻听知觉的限制性背侧纹状体门控功能的恢复。
