Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex
Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex
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DOI：
10.1177/0271678x17695291
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发表时间：
2018-02-01
影响因子：
6.3
通讯作者：
Mangia, Silvia
中科院分区：
文献类型：
--
作者：
Bednarik, Petr;Tkac, Ivan;Mangia, Silvia
在本研究中，我们的目的是确定人类视觉皮层在呈现彩色和非彩色刺激期间的代谢反应，已知这些刺激会优先激活对颜色或亮度特征具有不同敏感性的两个独立的神经元群（称为斑点和间斑点）。由于斑点和间斑点具有不同的细胞色素氧化酶（COX）含量和微血管化水平（即不同的葡萄糖氧化能力），因此可以预期在彩色刺激和非彩色刺激期间会出现不同的功能代谢反应。刺激经过优化，可引起与大胆氧合水平依赖 (BOLD) 对比测量的相似的神经元激活负荷。使用功能性 H-1 MRS 在 7 T 下对 12 名受试者的代谢反应进行了评估。在彩色和非彩色刺激期间，我们观察到谷氨酸和乳酸浓度典型增加，以及天冬氨酸和葡萄糖浓度下降，这表明葡萄糖氧化增加。然而，在检测灵敏度限度内，我们没有观察到彩色和非彩色刺激引起的代谢反应之间有任何差异。我们得出的结论是，尽管这些神经元群体的能力不同，但氧化代谢的类似增加支持了激活的斑点和间斑点的更高能量需求。
In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called blobs and interblobs) with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional H-1 MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.