Song Chen, Sandberg Kristian, Andersen Lau Møller, Blicher Jakob Udby, Rees Geraint
Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom,
Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom.
J Neurosci. 2017 Sep 13;37(37):8929-8937. doi: 10.1523/JNEUROSCI.3945-16.2017. Epub 2017 Aug 14.
GABA is the primary inhibitory neurotransmitter in human brain. The level of GABA varies substantially across individuals, and this variability is associated with interindividual differences in visual perception. However, it remains unclear whether the association between GABA level and visual perception reflects a general influence of visual inhibition or whether the GABA levels of different cortical regions selectively influence perception of different visual features. To address this, we studied how the GABA levels of parietal and occipital cortices related to interindividual differences in size, orientation, and brightness perception. We used visual contextual illusion as a perceptual assay since the illusion dissociates perceptual content from stimulus content and the magnitude of the illusion reflects the effect of visual inhibition. Across individuals, we observed selective correlations between the level of GABA and the magnitude of contextual illusion. Specifically, parietal GABA level correlated with size illusion magnitude but not with orientation or brightness illusion magnitude; in contrast, occipital GABA level correlated with orientation illusion magnitude but not with size or brightness illusion magnitude. Our findings reveal a region- and feature-dependent influence of GABA level on human visual perception. Parietal and occipital cortices contain, respectively, topographic maps of size and orientation preference in which neural responses to stimulus sizes and stimulus orientations are modulated by intraregional lateral connections. We propose that these lateral connections may underlie the selective influence of GABA on visual perception. GABA, the primary inhibitory neurotransmitter in human visual system, varies substantially across individuals. This interindividual variability in GABA level is linked to interindividual differences in many aspects of visual perception. However, the widespread influence of GABA raises the question of whether interindividual variability in GABA reflects an overall variability in visual inhibition and has a general influence on visual perception or whether the GABA levels of different cortical regions have selective influence on perception of different visual features. Here we report a region- and feature-dependent influence of GABA level on human visual perception. Our findings suggest that GABA level of a cortical region selectively influences perception of visual features that are topographically mapped in this region through intraregional lateral connections.
γ-氨基丁酸（GABA）是人类大脑中的主要抑制性神经递质。GABA水平在个体间差异很大，这种变异性与个体在视觉感知上的差异有关。然而，GABA水平与视觉感知之间的关联是反映了视觉抑制的普遍影响，还是不同皮质区域的GABA水平选择性地影响了对不同视觉特征的感知，目前尚不清楚。为了解决这个问题，我们研究了顶叶和枕叶皮质的GABA水平与个体在大小、方向和亮度感知差异之间的关系。我们使用视觉背景错觉作为一种感知测定方法，因为这种错觉将感知内容与刺激内容分离，并且错觉的程度反映了视觉抑制的效果。在个体中，我们观察到GABA水平与背景错觉程度之间存在选择性相关性。具体而言，顶叶GABA水平与大小错觉程度相关，但与方向或亮度错觉程度无关；相反，枕叶GABA水平与方向错觉程度相关，但与大小或亮度错觉程度无关。我们的研究结果揭示了GABA水平对人类视觉感知的区域和特征依赖性影响。顶叶和枕叶皮质分别包含大小和方向偏好的地形图，其中对刺激大小和刺激方向的神经反应由区域内的侧向连接调节。我们提出这些侧向连接可能是GABA对视觉感知产生选择性影响的基础。GABA是人类视觉系统中的主要抑制性神经递质，在个体间差异很大。GABA水平的这种个体间变异性与视觉感知许多方面的个体间差异有关。然而，GABA的广泛影响引发了一个问题，即GABA的个体间变异性是否反映了视觉抑制的总体变异性并对视觉感知有普遍影响，或者不同皮质区域的GABA水平是否对不同视觉特征的感知有选择性影响。在这里，我们报告了GABA水平对人类视觉感知的区域和特征依赖性影响。我们的研究结果表明，皮质区域的GABA水平通过区域内的侧向连接选择性地影响在该区域地形图上的视觉特征的感知。
