[Neurological deficits after section of the intertectal commissure in the cat]

The effects of cutting the intertectal commissure have been studied in three cats. After the operation all animals tended to look downwards, as if attracted by the ground. There was no paralysis of the head movements. However spontaneous vertical head movements necessary for exploring the space in front and especially above the animal were very rare. Visual field examination showed a clear neglect for stimuli presented in the upper hemifields. The intertectal commissure syndrome is interpreted as a consequence of a disruption of intertectal nervous circuits responsible for the exploration of the portion of the space above the animal's head.