• Neuroophthalmology
• vision

Disorders of visual perception can range from the ‘positive’ (hallucinations) to the ‘negative’ (visual agnosia in which a ‘visual percept is stripped of its meaning’). Understanding the broad sweep of these disorders has been advanced by functional neuroimaging and the concept of a ‘hodotopic framework’ comprising specialised cortical subregions (topology) and their connections (hodology) (see page 1280).1 The present neuropsychiatry review harnesses the hodotopic framework to concepts of CNS hyper- and hypofunction to create a new taxonomy of abnormal visual perception. Can this ‘periodic table’ of higher visual disorders supplant previous inventories of visual phenomenology based on irritative, inhibitory and release mechanisms?2 Mendeleev's initial table of the elements had empty …