Montero V M
Department of Neurophysiology, University of Wisconsin, Madison 53705, USA.
Neuroscience. 1997 Feb;76(4):1069-81. doi: 10.1016/s0306-4522(96)00417-4.
In normal rats exploring a novel, complex environment, in comparison to control nonexploring rats, there is induction of the FOS protein, a marker of neuronal activity, in all layers of the striate visual cortex (particularly in the granular and supragranular layers), in the stratum griseum superficiale of the superior colliculus, and in the dorsal lateral geniculate nucleus, as well as in all layers of the whiskers barrel field in the somatosensory cortex. A surprising finding was a selective activation of the visual sector of the thalamic reticular nucleus, in dorsocaudal parts of the nucleus. To the contrary, in visually deprived rats exploring a novel environment which would depend critically on whiskers tactile clues for exploration there was instead a selective activation of the somatic sector in central parts of the thalamic reticular nucleus, in conjunction with activation of cortical whiskers barrel field. From these results it is concluded: (1) Different sensory sectors of the rat thalamic reticular nucleus are activated depending on prevalent sensory channels used in recognition of the environment, suggesting a role of thalamic reticular nucleus in optimizing thalamocortical transmission of essential external cues to guide adequate behaviour. (2) In the awake state, the granular and supragranular layers of the visual and somatosensory cortices are more active when attention is paid to sensory stimuli that are essential for recognition of the environment. (3) The selective induction of c-fos in the visual and somatosensory cortices, and in the stratum griseum superficiale of superior colliculus of rats exploring a novel, complex environment might be related to plastic changes that have been demonstrated in these centres in rats raised in complex environments. These plastic changes are likely to be the result of target late-response genes activated by c-fos.
在探索新奇复杂环境的正常大鼠中，与未进行探索的对照大鼠相比，纹状视觉皮层的所有层（特别是颗粒层和颗粒上层）、上丘浅层以及背外侧膝状体核中，都会诱导出FOS蛋白（一种神经元活动的标志物），体感皮层的胡须桶状区的所有层中也会出现这种情况。一个惊人的发现是丘脑网状核视觉区在该核背尾侧部分有选择性激活。相反，在视觉剥夺的大鼠探索一个严重依赖胡须触觉线索进行探索的新奇环境时，丘脑网状核中部的躯体感觉区会出现选择性激活，同时伴有皮层胡须桶状区的激活。从这些结果可以得出以下结论：（1）大鼠丘脑网状核的不同感觉区会根据识别环境时所使用的主要感觉通道而被激活，这表明丘脑网状核在优化丘脑皮质将基本外部线索传递以指导适当行为方面发挥作用。（2）在清醒状态下，当关注对识别环境至关重要的感觉刺激时，视觉和体感皮层的颗粒层和颗粒上层会更活跃。（3）在探索新奇复杂环境的大鼠的视觉和体感皮层以及上丘浅层中，c-fos的选择性诱导可能与在复杂环境中饲养的大鼠这些中枢所显示的可塑性变化有关。这些可塑性变化可能是由c-fos激活的靶标晚期反应基因的结果。
