Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Rd. NW, Washington, DC 20007, USA.
Brain Res. 2012 Nov 16;1485:22-39. doi: 10.1016/j.brainres.2012.08.052. Epub 2012 Sep 6.
It has long been known that subjective tinnitus, a constant or intermittent phantom sound perceived by 10 to 15% of the adult population, is not a purely auditory phenomenon but is also tied to limbic-related brain regions. Supporting evidence comes from data indicating that stress and emotion can modulate tinnitus, and from brain imaging studies showing functional and anatomical differences in limbic-related brain regions of tinnitus patients and controls. Recent studies from our lab revealed altered blood oxygen level-dependent (BOLD) responses to stimulation at the tinnitus frequency in the ventral striatum (specifically, the nucleus accumbens) and gray-matter reductions (i.e., anatomical changes) in ventromedial prefrontal cortex (vmPFC), of tinnitus patients compared to controls. The present study extended these findings by demonstrating functional differences in vmPFC between 20 tinnitus patients and 20 age-matched controls. Importantly, the observed BOLD response in vmPFC was positively correlated with tinnitus characteristics such as subjective loudness and the percent of time during which the tinnitus was perceived, whereas correlations with tinnitus handicap inventory scores and other variables known to be affected in tinnitus (e.g., depression, anxiety, noise sensitivity, hearing loss) were weaker or absent. This suggests that the observed group differences are indeed related to the strength of the tinnitus percept and not to an affective reaction to tinnitus. The results further corroborate vmPFC as a region of high interest for tinnitus research.This article is part of a Special Issue entitled: Tinnitus Neuroscience.
长期以来，人们一直知道主观耳鸣，即 10%至 15%的成年人感知到的持续或间歇性幻听，不仅仅是一种纯粹的听觉现象，还与边缘相关的大脑区域有关。有证据表明，压力和情绪可以调节耳鸣，大脑成像研究也显示耳鸣患者和对照组的边缘相关大脑区域在功能和解剖结构上存在差异，这为这一观点提供了支持。我们实验室的最近研究表明，与对照组相比，耳鸣患者的腹侧纹状体（特别是伏隔核）对耳鸣频率的刺激的血氧水平依赖（BOLD）反应发生改变，并且在腹内侧前额叶皮层（vmPFC）中灰质减少（即解剖结构改变）。本研究通过在 20 名耳鸣患者和 20 名年龄匹配的对照组之间的 vmPFC 中显示功能差异，扩展了这些发现。重要的是，vmPFC 中的 BOLD 反应与耳鸣特征（如主观响度和感知耳鸣的时间百分比）呈正相关，而与耳鸣障碍量表评分和其他已知受耳鸣影响的变量（如抑郁、焦虑、噪声敏感性、听力损失）的相关性较弱或不存在。这表明观察到的组间差异确实与耳鸣感知的强度有关，而与对耳鸣的情感反应无关。该结果进一步证实 vmPFC 是耳鸣研究的一个重要区域。本文是特刊“耳鸣神经科学”的一部分。
