GABA and Glutamate in hMT+ Link to Individual Differences in Residual Visual Function After Occipital Stroke.
GABA and Glutamate in hMT+ Link to Individual Differences in Residual Visual Function After Occipital Stroke.
复制标题
作者：
枕骨中风后初级视觉皮质的损伤会导致对侧大脑半球有意识的视觉丧失。然而，一些患者保留了在他们的盲区内检测运动视觉刺激的能力。本研究探讨了初级视觉皮层丧失后盲场知觉的个体差异是否可以用神经递质γ-氨基丁酸和谷氨酸的浓度或视觉运动处理的活性来解释。对19例慢性枕卒中患者进行磁共振成像，测定神经递质GABA和谷氨酸的浓度(质子磁共振波谱)和HMT+的功能活性(功能磁共振成像)。我们还使用高对比度、移动的Gabor斑块对每个参与者进行了两个间隔的强制选择检测任务。然后，我们测量和评估了参与者在盲区的残余视力和体内神经递质浓度之间的关系强度，以及他们HMT+中视觉诱发的功能性磁共振成像活动。同时还测量了作为对照的感觉运动区的GABA和谷氨酸水平。磁共振光谱学得出的HMT+(但不是感觉运动皮质)中的GABA和谷氨酸浓度强烈地预测了盲区视觉检测能力。成绩与HMT+中抑制性和兴奋性神经递质的水平呈负相关，但令人惊讶的是，与这个运动敏感区域视觉诱发的血氧水平依赖的信号变化无关。与血氧水平依赖的信号变化相比，HMT+中的GABA和谷氨酸水平似乎提供了有关周边定义盲区内运动检测能力的更好信息-本质上，作为盲区残余视觉处理质量的生物标记物。它们是否也反映了成功恢复视功能的潜力仍有待确定。
Damage to the primary visual cortex following an occipital stroke causes loss of conscious vision in the contralateral hemifield. Yet, some patients retain the ability to detect moving visual stimuli within their blind field. The present study asked whether such individual differences in blind field perception following loss of primary visual cortex could be explained by the concentration of neurotransmitters γ-aminobutyric acid (GABA) and glutamate or activity of the visual motion processing, human middle temporal complex (hMT+). We used magnetic resonance imaging in 19 patients with chronic occipital stroke to measure the concentration of neurotransmitters GABA and glutamate (proton magnetic resonance spectroscopy) and functional activity in hMT+ (functional magnetic resonance imaging). We also tested each participant on a 2-interval forced choice detection task using high-contrast, moving Gabor patches. We then measured and assessed the strength of relationships between participants’ residual vision in their blind field and in vivo neurotransmitter concentrations, as well as visually evoked functional magnetic resonance imaging activity in their hMT+. Levels of GABA and glutamate were also measured in a sensorimotor region, which served as a control. Magnetic resonance spectroscopy-derived GABA and glutamate concentrations in hMT+ (but not sensorimotor cortex) strongly predicted blind-field visual detection abilities. Performance was inversely related to levels of both inhibitory and excitatory neurotransmitters in hMT+ but, surprisingly, did not correlate with visually evoked blood oxygenation level–dependent signal change in this motion-sensitive region. Levels of GABA and glutamate in hMT+ appear to provide superior information about motion detection capabilities inside perimetrically defined blind fields compared to blood oxygenation level–dependent signal changes—in essence, serving as biomarkers for the quality of residual visual processing in the blind-field. Whether they also reflect a potential for successful rehabilitation of visual function remains to be determined.
影响因子：
5.7
作者：
Papanikolaou A;Keliris GA;Papageorgiou TD;Schiefer U;Logothetis NK;Smirnakis SM
通讯作者：
Smirnakis SM