Characterization of mouse visual cortex

Although the mouse is a popular model in scientific research, little is known about its visual system, probably because mice rely more on olfactory and somatosensory cues. As a consequence no consensus exists about its structural organisation. It is however a potential model for developmental or injury-induced brain plasticity, since there is a vast array of commercially available knock-outs, which could help elucidating the causal relationship between molecular expression patterns and neocortical plasticity. In this study we investigated the main anatomical characteristics of the mouse visual cortex through in situ hybridisation and immunocytochemistry for neuronal activity markers. Our goal was to delineate the full extent of the cortical regions processing visual information and to identify monocularly and binocularly driven regions within the visual cortex. We therefore analyzed the cortex of monocularly and binocularly enucleated mice versus that of visually-stimulated controls. The binocularly enucleated mice show a clear-cut lateral border between visual and non-visual cortex but a transition zone between visual and retrosplenial cortex. In monocularly enucleated mice, the visual cortex ipsilateral of the deprived eye displayed clearly lower signals than the contralateral cortex. Within this region of basal activity we could identify multiple regions of high activity. This suggests a monocular zone not only within V1, but also in different higher order visual areas.status: publishe