Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, CF103AT Cardiff, United Kingdom.
J Neurosci. 2011 Nov 16;31(46):16556-60. doi: 10.1523/JNEUROSCI.4489-11.2011.
The neural mechanisms underlying variability in human sensory perception remain incompletely understood. In particular, few studies have attempted to investigate the relationship between in vivo measurements of neurochemistry and individuals' behavioral performance. Our previous work found a relationship between GABA concentration in the visual cortex and orientation discrimination thresholds (Edden et al., 2009). In the present study, we used magnetic resonance spectroscopy of GABA and psychophysical testing of vibrotactile frequency thresholds to investigate whether individual differences in tactile frequency discrimination performance are correlated with GABA concentration in sensorimotor cortex. Behaviorally, individuals showed a wide range of discrimination thresholds ranging from 3 to 7.6 Hz around the 25 Hz standard. These frequency discrimination thresholds were significantly correlated with GABA concentration (r = -0.58; p < 0.05) in individuals' sensorimotor cortex, but not with GABA concentration in an occipital control region (r = -0.04). These results demonstrate a link between GABA concentration and frequency discrimination in vivo, and support the hypothesis that GABAergic mechanisms have an important role to play in sensory discrimination.
人类感官知觉变化的神经机制仍不完全清楚。特别是，很少有研究试图调查神经化学的体内测量与个体行为表现之间的关系。我们之前的工作发现了视觉皮层中 GABA 浓度与方向辨别阈值之间的关系（Edden 等人，2009 年）。在本研究中，我们使用 GABA 的磁共振波谱和振动触觉频率阈值的心理物理学测试来研究触觉频率辨别性能的个体差异是否与感觉运动皮层中的 GABA 浓度相关。行为上，个体在围绕 25Hz 标准的 3 到 7.6Hz 范围内表现出广泛的辨别阈值。这些频率辨别阈值与个体感觉运动皮层中的 GABA 浓度呈显著负相关（r = -0.58;p <0.05），但与枕叶对照区域的 GABA 浓度无关（r = -0.04）。这些结果表明体内 GABA 浓度与频率辨别之间存在联系，并支持 GABA 能机制在感觉辨别中起重要作用的假设。
