Jueptner M, Weiller C
Department of Neurology, University Clinics, Essen, Germany.
Neuroimage. 1995 Jun;2(2):148-56. doi: 10.1006/nimg.1995.1017.
The energy metabolism of the adult human brain almost completely depends on glucose. The functional coupling of regional cerebral blood flow and local cerebral glucose metabolism has been established in a wide range of experiments using autoradiographic techniques in rats, cats, and monkeys as well as double-tracer techniques in humans. Glucose utilization in turn reflects neuronal activity and more specifically synaptic, mainly presynaptic, activity. The majority of glucose is needed for the maintenance of membrane potentials and restoration of ion gradients. PET as well as fMRI may be used to study changes in blood flow or flow-related phenomena in human subjects in vivo. Both techniques monitor changes of synaptic activity in a population of cells. These changes may be due to excitation or inhibition. More than 85% of cerebral glucose is used by neurons (mainly presynaptic axon terminals), while the remainder may at least partly account for metabolic processes in glial cells. Monitoring of regional cerebral blood flow with PET or fMRI thus mainly reflects neuronal and more specifically (pre-) synaptic activity.
成人大脑的能量代谢几乎完全依赖于葡萄糖。在大鼠、猫和猴子身上使用放射自显影技术以及在人类身上使用双示踪技术的大量实验已经证实了局部脑血流与局部脑葡萄糖代谢之间的功能耦合。葡萄糖利用反过来反映神经元活动，更具体地说是突触活动，主要是突触前活动。大部分葡萄糖用于维持膜电位和恢复离子梯度。正电子发射断层扫描（PET）以及功能磁共振成像（fMRI）可用于研究人类受试者体内血流变化或与血流相关的现象。这两种技术都监测一群细胞中突触活动的变化。这些变化可能是由于兴奋或抑制引起的。超过85%的脑葡萄糖被神经元（主要是突触前轴突终末）利用，而其余部分可能至少部分用于神经胶质细胞的代谢过程。因此，用PET或fMRI监测局部脑血流主要反映神经元活动，更具体地说是（突触前）突触活动。
