Kasamatsu T, Heggelund P
Exp Brain Res. 1982;45(3):317-27. doi: 10.1007/BF01208591.
We studied how iontophoresis of noradrenaline (NA) changes responsiveness of individual cells in the feline visual cortex when their visual receptive fields are stimulated with the appropriate visual stimulus. We found three populations of cortical cells which either increased, decreased or did not change their visual responsiveness during NA iontophoresis. About equal numbers of cells belonged to each of these three groups. In the majority of such cells that changed visual responsiveness during NA iontophoresis and that had measureable amounts of spontaneous activity, the ratio of visually evoked to spontaneous activity (signal-to-noise ratio) improved during NA iontophoresis. This improvement was independent of the direction of changes in the response magnitude to visual stimulation. There was a differential effect of NA on simple and complex visual cortical cells: Although most simple cells (86%) clearly changed their responsiveness during NA iontophoresis, the effects were seen in only one-third of complex cells. Furthermore, the effects on complex cells were usually weak compared to those typically seen in simple cells. In some cases the effects of NA were more complicated than an overall enhancement of suppression of the cortical cell's responses to visual stimulation. The possible dual role of NA in the visual cortex is briefly discussed.
我们研究了在猫视觉皮层中，当用适当的视觉刺激激发单个细胞的视觉感受野时，去甲肾上腺素（NA）的离子电渗疗法如何改变这些细胞的反应性。我们发现了三类皮层细胞，在NA离子电渗疗法期间，它们的视觉反应性要么增强、要么减弱、要么没有变化。这三组中每组细胞的数量大致相等。在大多数在NA离子电渗疗法期间改变视觉反应性且有可测量自发活动量的此类细胞中，在NA离子电渗疗法期间，视觉诱发活动与自发活动的比率（信噪比）有所改善。这种改善与对视觉刺激反应幅度变化的方向无关。NA对简单和复杂视觉皮层细胞有不同的影响：虽然大多数简单细胞（86%）在NA离子电渗疗法期间明显改变了它们的反应性，但在只有三分之一的复杂细胞中观察到了这种影响。此外，与通常在简单细胞中看到的影响相比，对复杂细胞的影响通常较弱。在某些情况下，NA的影响比皮层细胞对视觉刺激反应的整体增强或抑制更为复杂。文中简要讨论了NA在视觉皮层中可能的双重作用。
