Neurometabolic coupling between neural activity, glucose, and lactate in activated visual cortex.
Neurometabolic coupling between neural activity, glucose, and lactate in activated visual cortex.
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DOI：
10.1111/jnc.13143
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发表时间：
2015-11
影响因子：
4.7
通讯作者：
Freeman RD
中科院分区：
文献类型：
--
作者：
Li B;Freeman RD
神经活动与能量代谢密切相关，但这种联系的细节仍有待确定。一个基本领域涉及神经活动与葡萄糖和乳酸的主要支持底物之间的关系。这对无创神经成像的解释具有重要意义。在这里，我们使用具有高的空间和时间分辨率的微电极，以确定在猫的大脑皮层的视觉激活过程中的葡萄糖，乳酸和神经活动的同时共定位的变化。组织葡萄糖和乳酸的浓度水平与电化学微电极测量，而神经尖峰活动和局部场电位采样的微电极。这些测量是同时进行的，而神经元被激活的视觉刺激不同的对比度水平，方向和大小。我们发现在神经激活过程中，组织葡萄糖浓度立即降低，同时乳酸增加。当神经元停止放电时，葡萄糖和乳酸信号立即恢复到基线水平。视觉刺激不会引起葡萄糖或乳酸信号的持续变化或初始下降。然而，脑血流量（CBF）和神经活动的共定位测量表明CBF信号的明显延迟，使得它在时间上与神经反应不相关。这些结果提供了关于在生理刺激期间共定位能量代谢和神经活动之间的耦合的直接实时证据。它们也与当前关于乳酸在神经激活期间大脑能量代谢中的作用的问题有关。
Neural activity is closely coupled with energy metabolism but details of the association remain to be identified. One basic area involves the relationships between neural activity and the main supportive substrates of glucose and lactate. This is of fundamental significance for the interpretation of non-invasive neural imaging. Here, we use microelectrodes with high spatial and temporal resolution to determine simultaneous co-localized changes in glucose, lactate and neural activity during visual activation of the cerebral cortex in the cat. Tissue glucose and lactate concentration levels are measured with electrochemical microelectrodes while neural spiking activity and local field potentials are sampled by a microelectrode. These measurements are performed simultaneously while neurons are activated by visual stimuli of different contrast levels, orientations, and sizes. We find immediate decreases in tissue glucose concentration and simultaneous increases in lactate during neural activation. Both glucose and lactate signals return to their baseline levels instantly as neurons cease firing. No sustained changes or initial dips in glucose or lactate signals are elicited by visual stimulation. However, co-localized measurements of cerebral blood flow (CBF) and neural activity demonstrate a clear delay in the CBF signal such that it does not correlate temporally with the neural response. These results provide direct real-time evidence regarding the coupling between co-localized energy metabolism and neural activity during physiological stimulation. They are also relevant to a current question regarding the role of lactate in energy metabolism in the brain during neural activation.