Unilateral cerebral ischemia inhibits optomotor responses of the ipsilateral eye in mice

A reduction in blood flow to the brain causes stroke and damage to neuronal networks. Cerebral ischemia is frequently associated with loss of visual functions. Because retinal and small cerebral vessels are vulnerable to similar risk factors, the loss of vision could result from concurrent retinal ischemia, and it is not clear if visual functions may be inhibited by cerebral ischemia directly. In this study, the distal middle cerebral artery in the right hemisphere of mice was occluded to produce unilateral cerebral ischemia and subsequent infarction. The layer V neurons expressing YFP in transgenic yellow fluorescent protein in transgenic B6.Cg-Tg(Thy1-YFPH)2Jrs/J mice disappeared in the motor and somatosensory cortex, but not in the visual area. The latencies of flash visual evoked potential recorded from two hemispheres were imbalanced, but did not differ markedly from the latencies recorded in controls. However, the optomotor responses of the ipsilateral eye were significantly reduced by 48 h after occlusion. Our results suggest that focused cerebral ischemia may inhibit ipsilateral eye movement in the absence of damage to the visual cortex. This study may provide a platform for further investigation of the relationship between cortical ischemia and visual function.