SUSTAINED NEURONAL TOTAL TITLE IN DESCRIPTION

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者的研究机构。 持续的神经元激活将氧化代谢提高到一个新的稳态水平：来自人类视觉皮层（1）H NMR光谱的证据 迄今为止，功能（1）H NMR光谱已被用来报告的时间进程的几个代谢产物，主要是乳酸。利用超高磁场（7 T）的灵敏度，在5.3和10.6min的两种视觉刺激模式下，测定了人视皮层中17种代谢物的浓度。观察到几种代谢物的浓度显著变化约为0.2 mumol/g：乳酸增加23%+/-5%（P<0.0005），谷氨酸增加3%+/-1%（P<0.01），而天冬氨酸减少15%+/-6%（P<0.05）。葡萄糖浓度也表现出在激活期间降低的趋势。乳酸浓度在激活的第一分钟内达到新的稳态水平，并且仅在刺激结束后才回到基线。代谢物浓度的变化意味着在激活过程中氧化代谢上升到一个新的稳态水平，并表明氨基酸稳态受到生理刺激的影响，可能是因为通过苹果酸-天冬氨酸穿梭的通量增加

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Sustained neuronal activation raises oxidative metabolism to a new steady-state level: evidence from (1)H NMR spectroscopy in the human visual cortex To date, functional (1)H NMR spectroscopy has been utilized to report the time courses of few metabolites, primarily lactate. Benefiting from the sensitivity offered by ultra-high magnetic field (7 T), the concentrations of 17 metabolites were measured in the human visual cortex during two paradigms of visual stimulation lasting 5.3 and 10.6 mins. Significant concentration changes of approximately 0.2 mumol/g were observed for several metabolites: lactate increased by 23%+/-5% (P<0.0005), glutamate increased by 3%+/-1% (P<0.01), whereas aspartate decreased by 15%+/-6% (P<0.05). Glucose concentration also manifested a tendency to decrease during activation periods. The lactate concentration reached the new steady-state level within the first minute of activation and came back to baseline only after the stimulus ended. The changes of the concentration of metabolites implied a rise in oxidative metabolism to a new steady-state level during activation and indicated that amino-acid homeostasis is affected by physiological stimulation, likely because of an increased flux through the malate-aspartate shuttle