Corneal Reflex in Hemisphere Disease II

Summary In man, contralateral cerebral decortication or removal of a hemisphere does not permanently abolish the corneal reflex. Destruction of the contralateral thalamus or contralateral mesencephalic trigeminal tract does abolish the corneal reflex. In the cat however, the corneal reflex remains intact after contralateral decortication, he mi sphere ctomy and total ablation of the thalamus. Some of these procedures diminished the corneal reflex or increased the threshold, but neither of these changes were seen for more than a few days post-operativ ely. In this animal however, the second reflex response, evoked by supra orbital nerve stimulation, is abolished by certain thalamic lesions and by contralateral hemi-transection of the brain stem at various levels.