Viswanathan Ahalya, Freeman Ralph D
Group in Vision Science, School of Optometry, Helen Wills Neurosciences Institute, University of California, Berkeley, California 94720-2020, USA.
Nat Neurosci. 2007 Oct;10(10):1308-12. doi: 10.1038/nn1977. Epub 2007 Sep 9.
In noninvasive neuroimaging, neural activity is inferred from local fluctuations in deoxyhemoglobin. A fundamental question of functional magnetic resonance imaging (fMRI) is whether the inferred neural activity is driven primarily by synaptic or spiking activity. The answer is critical for the interpretation of the blood oxygen level-dependent (BOLD) signal in fMRI. Here, we have used well-established visual-system circuitry to create a stimulus that elicits synaptic activity without associated spike discharge. In colocalized recordings of neural and metabolic activity in cat primary visual cortex, we observed strong coupling between local field potentials (LFPs) and changes in tissue oxygen concentration in the absence of spikes. These results imply that the BOLD signal is more closely coupled to synaptic activity.
在无创神经成像中，神经活动是根据脱氧血红蛋白的局部波动推断出来的。功能磁共振成像（fMRI）的一个基本问题是，推断出的神经活动主要是由突触活动还是尖峰活动驱动的。这个答案对于解释fMRI中的血氧水平依赖（BOLD）信号至关重要。在这里，我们利用成熟的视觉系统电路创建了一种刺激，该刺激能引发突触活动而不伴有尖峰放电。在猫初级视觉皮层的神经和代谢活动的共定位记录中，我们观察到在没有尖峰的情况下，局部场电位（LFP）与组织氧浓度变化之间存在强耦合。这些结果表明，BOLD信号与突触活动的耦合更为紧密。
