A tonic hyperpolarization underlying contrast adaptation in cat visual cortex
A tonic hyperpolarization underlying contrast adaptation in cat visual cortex
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DOI：
10.1126/science.276.5314.949
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发表时间：
1997-05-09
期刊：
影响因子：
56.9
通讯作者：
Ferster, D
中科院分区：
文献类型：
--
作者：
Carandini, M;Ferster, D
初级视皮层神经元的放电率反应随刺激对比度（图像亮度相对于平均亮度的变化）而增长。然而，这些反应在细胞长时间暴露于高对比度视觉刺激后会减少，这种现象称为对比度适应，发生在皮层中，并且在视觉处理的早期阶段不存在。为了研究皮层适应的细胞机制，在猫的视皮层进行细胞内记录，并研究了长时间视觉刺激的影响。令人惊讶的是，对比度适应几乎没有影响皮层细胞膜电位的刺激驱动的调制。此外，它没有产生相当大的变化，膜电阻。适应的主要影响，明显的存在和不存在的视觉刺激，是紧张性超极化。适应影响一类突触输入，最有可能是兴奋性的，对皮层细胞产生紧张性影响。
The firing rate responses of neurons in the primary visual cortex grow with stimulus contrast, the variation in the luminance of an image relative to the mean luminance. These responses, however, are reduced after a cell is exposed for prolonged periods to high-contrast visual stimuli, This phenomenon, known as contrast adaptation, occurs in the cortex and is not present at earlier stages of visual processing. To investigate the cellular mechanisms underlying cortical adaptation, intracellular recordings were performed in the visual cortex of cats, and the effects of prolonged visual stimulation were studied. Surprisingly, contrast adaptation barely affected the stimulus-driven modulations in the membrane potential of cortical cells. Moreover, it did not produce sizable changes in membrane resistance. The major effect of adaptation, evident both in the presence and in the absence of a visual stimulus, was a tonic hyperpolarization. Adaptation affects a class of synaptic inputs, most likely excitatory in nature, that exert a tonic influence on cortical cells.