Anderson J, Lampl I, Reichova I, Carandini M, Ferster D
Department of Neurobiology and Physiology, Northwestern University, 2153 North Campus Drive, Evanston, Illinois 60208, USA.
Nat Neurosci. 2000 Jun;3(6):617-21. doi: 10.1038/75797.
Membrane potentials of cortical neurons fluctuate between a hyperpolarized ('down') state and a depolarized ('up') state which may be separated by up to 30 mV, reflecting rapid but infrequent transitions between two patterns of synaptic input. Here we show that such fluctuations may contribute to representation of visual stimuli by cortical cells. In complex cells of anesthetized cats, where such fluctuations are most prominent, prolonged visual stimulation increased the probability of the up state. This probability increase was related to stimulus strength: its dependence on stimulus orientation and contrast matched each cell's averaged membrane potential. Thus large fluctuations in membrane potential are not simply noise on which visual responses are superimposed, but may provide a substrate for encoding sensory information.
皮层神经元的膜电位在超极化（“向下”）状态和去极化（“向上”）状态之间波动，这两种状态之间的电位差可达30 mV，反映了两种突触输入模式之间快速但不频繁的转换。我们在此表明，这种波动可能有助于皮层细胞对视觉刺激的表征。在麻醉猫的复杂细胞中，这种波动最为显著，长时间的视觉刺激增加了向上状态的概率。这种概率增加与刺激强度有关：其对刺激方向和对比度的依赖性与每个细胞的平均膜电位相匹配。因此，膜电位的大幅波动并非仅仅是叠加视觉反应的噪声，而是可能为编码感觉信息提供了一个基础。
