Author:

Abstract:

Central retinal lesions lead to a topographical reorganization within the lesion projection zone (LPZ) in adult cat visual cortex. This recovery coincides with changes in activity balance and gene expression. We investigated alterations in cortical activity in area 17 in function of post-lesion survival time. For this purpose, we used in situ hybridisation for zif268 to visualise the LPZ in the visual cortex of the retinal lesion cat (RLC). Furthermore, we quantified the neuronal activity by means of real-time PCR for c-fos in area 17 of the RLC. First, we compared the activity level of the central LPZ to the peripheral intact projection zone (IPZ) along the medio-lateral axis of the brain. Second, we examined the activity gradient along the posterior-anterior axis of area 17. Our study on the effect of retinal lesions in area 17 revealed a strong activity decrease in the LPZ along the two axes. Both axes exhibited a recovery of activity, implying that the LPZ became smaller in function of survival time. We provided indisputable evidence that the central retinal lesions also had a time-dependent influence on the activity of the peripheral IPZ. We conclude that changes in activity of the LPZ as well as the IPZ have an important role in processes of plasticity-mediated recovery.