Imamura Kazuyuki, Tanaka Shigeru, Ribot Jérôme, Kobayashi Masayuki, Yamamoto Masao, Nakadate Kazuhiko, Watanabe Yasuyoshi
Laboratory for Visual Neurocomputing, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
Eur J Neurosci. 2006 Apr;23(8):2087-98. doi: 10.1111/j.1460-9568.2006.04729.x.
We investigated how neural function is preserved or matured in the visual cortex of cats, following the induction of hydrocephalus by kaolin injection. In vivo optical imaging of intrinsic signals in 11-17-week-old hydrocephalic cats revealed orientation maps showing the orderly arrangement of preferred orientations when stimulated by grating stimuli at a low spatial frequency, whereas stimulus-evoked intrinsic signals in response to gratings at a high spatial frequency were often too weak to construct orientation maps. Furthermore, in two of the three hydrocephalic cats, initially deteriorated orientation maps became almost regular maps in the second imaging experiments conducted 8 and 11 weeks, respectively, after the first imaging. This indicates that, despite large structural deformation of the hydrocephalic brain, orientation maps are elaborated sufficiently after the age of 5-6 months, by which time the orientation map formation is usually completed in normal cats. Single unit recording from the decompressed visual cortex revealed that many neurons showed normal orientation selectivity, whereas the binocularity of these neurons was found to be reduced. These results suggested that the deformed visual cortex of hydrocephalic cats exhibits a high plasticity, retaining its functional organization.
我们研究了通过注射高岭土诱导脑积水后，猫视觉皮层中的神经功能是如何得以保留或成熟的。对11 - 17周龄脑积水猫的内在信号进行体内光学成像，结果显示，当用低空间频率的光栅刺激时，取向图呈现出偏好取向的有序排列，而对高空间频率光栅的刺激诱发内在信号往往太弱，无法构建取向图。此外，在三只脑积水猫中的两只中，最初恶化的取向图在第一次成像后的第8周和第11周分别进行的第二次成像实验中几乎变成了规则的图。这表明，尽管脑积水大脑存在较大的结构变形，但在5 - 6个月龄后，取向图仍能充分形成，而在正常猫中，此时取向图的形成通常已经完成。对减压视觉皮层进行单单位记录发现，许多神经元表现出正常的取向选择性，然而这些神经元的双眼性被发现有所降低。这些结果表明，脑积水猫变形的视觉皮层表现出高度的可塑性，保留了其功能组织。
