• visual hallucinations
• primary visual cortex
• extrastriate visual cortical area

. . . il voit les Bâtiments s’élever sous ses yeux et lui offrir toutes les Parties qui entrent dans leur Construction extérieure.¹

Charles Bonnet’s visually impaired grandfather, although remembered (through the eponymous syndrome) for his hallucinations of figures, animals, and objects, also saw brickwork and scaffolding patterns. Largely ignored in the literature, these grid-like phenomena are experienced by more than 70% of patients with visual hallucinations secondary to eye disease. They are also reported by patients with visual pathway infarcts and by normal sighted subjects during visual sensory …