Persistence of the blink reflex to sudden illumination in a comatose patient. A clinical and pathologic study.

A persistent blink reflex to light (BRL) was observed in a patient who became comatose after a cardiac arrest. Postmortem examination revealed severe hypoxic ganglion cell necrosis of the cerebral and cerebellar cortex, the basal ganglia, the hypothalamus, nuclei in the brain stem, and the superior colliculi. The pretectum was unaffected. These findings suggest that the afferent fibers of the BRL enter the brain stem not in the superior colliculus, but in the pretectum.