Videen T O, Daw N W, Rader R K
J Neurosci. 1984 Jun;4(6):1607-17. doi: 10.1523/JNEUROSCI.04-06-01607.1984.
The responses of visual cortical neurons during iontophoresis of norepinephrine (NE) were compared in kittens and adult cats. One type of neuronal "plasticity" (the ability of visual cortical neurons to have their response properties markedly altered during exposure to a restricted visual environment) normally occurs only in young kittens and has been hypothesized to depend on the presence of NE. We investigated this hypothesis in terms of a model of synaptic plasticity which suggested that NE would selectively enhance the evoked responses of neurons and that this enhancement might exist to a greater extent in kittens than in adult cats. The responses of 72% (43 of 60) of all neurons sampled decreased during NE iontophoresis, while the responses of only a few neurons (3 of 60) increased. Reduced activity occurred in roughly equal percentages of simple and complex cells. We also looked for differences in NE modulation of the "signal-to-noise" ratio of neurons. Most neurons had little spontaneous activity, but, of those that did, the signal-to-noise ratio increased in some instances and decreased in others. No difference in any of the effects of NE was observed between kittens and adult cats. The role of NE in cortical plasticity is discussed.
在小猫和成年猫中比较了去甲肾上腺素（NE）离子电渗疗法期间视觉皮层神经元的反应。一种神经元“可塑性”（视觉皮层神经元在受限视觉环境暴露期间其反应特性明显改变的能力）通常仅发生在幼小猫中，并且据推测依赖于NE的存在。我们根据突触可塑性模型研究了这一假设，该模型表明NE会选择性增强神经元的诱发反应，并且这种增强在小猫中可能比在成年猫中更大程度地存在。在NE离子电渗疗法期间，所有采样神经元中有72%（60个中的43个）的反应降低，而只有少数神经元（60个中的3个）的反应增加。简单细胞和复杂细胞中出现活动减少的比例大致相等。我们还研究了NE对神经元“信噪比”调节的差异。大多数神经元几乎没有自发活动，但是，在有自发活动的那些神经元中，信噪比在某些情况下增加而在其他情况下降低。在小猫和成年猫之间未观察到NE的任何效应存在差异。讨论了NE在皮层可塑性中的作用。
