The relative metabolic demand of inhibition and excitation
The relative metabolic demand of inhibition and excitation
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DOI：
10.1038/35023171
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发表时间：
2000-08
期刊：
影响因子：
64.8
通讯作者：
D. Waldvogel;P. Gelderen;W. Muellbacher;U. Ziemann;I. Immisch;M. Hallett
中科院分区：
文献类型：
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作者：
D. Waldvogel;P. Gelderen;W. Muellbacher;U. Ziemann;I. Immisch;M. Hallett
通过使用 (14C)2-脱氧葡萄糖方法，抑制已被证明是突触水平的代谢活跃过程。磁共振波谱的最新结果支持了这一点，该波谱将功能激活时发生的神经能量学变化与神经递质循环联系起来。然而，抑制性突触数量较少，并且位置比兴奋性突触更好，这表明抑制可能比兴奋更有效，因此消耗的能量更少。在这里，我们使用事件相关的功能磁共振成像对志愿者进行测试，这些志愿者的运动皮层在“进行/不进行”任务的“不进行”条件下受到抑制，如经颅磁刺激所证明的那样。与兴奋不同，抑制不会引起运动皮层中血氧水平依赖性信号的可测量变化，这表明抑制对代谢的要求较低。因此，功能成像研究中看到的“激活”可能是兴奋而不是抑制的结果。
By using the (14C)2-deoxyglucose method, inhibition has been shown to be a metabolically active process at the level of the synapse,. This is supported by recent results from magnetic resonance spectroscopy that related the changes in neuroenergetics occurring with functional activation to neurotransmitter cycling. However, inhibitory synapses are less numerous and strategically better located than excitatory synapses, indicating that inhibition may be more efficient, and therefore less energy-consuming, than excitation. Here we test this hypothesis using event-related functional magnetic resonance imaging in volunteers whose motor cortex was inhibited during the no-go condition of a go/no-go task, as demonstrated by transcranial magnetic stimulation. Unlike excitation, inhibition evoked no measurable change in the blood-oxygenation-level-dependent signal in the motor cortex, indicating that inhibition is less metabolically demanding. Therefore, the ‘activation’ seen in functional imaging studies probably results from excitation rather than inhibition.