In contrast, the surrounding cortex received more complex inputs, implying a visuopsychic

function, further elaborated through temporal and frontal projections. A link between the geniculo-striate pathway and visual hallucinations had first been recognized in 1886 by Seguin,9 who described the occurrence of visual hallucinations within a Inhibitors,research,lifescience,medical visual field defect. De Morsier had presented a case at an international congress in London in 1935 with hemifield visual hallucinations without a visual field defect, and had concluded that visual hallucinations could also be associated with lesions of the paravisual sphere, a term he attributed to Hoff and Pötzl describing connections between the TW-37 in vitro pulvinar and visual cortices (see ref 10 for a recent anatomical description). Visual hallucinatory syndromes past: de Morsier’s syndromes De Morsier’s 1936 and 1938 papers viewed visual hallucinations as a stereotyped automatism of the broadly defined visual system including the paravisual Inhibitors,research,lifescience,medical sphere and temporal lobes. Damage to Inhibitors,research,lifescience,medical the system at different locations would associate visual hallucinations with varying combinations

of motor, vestibular, and auditory symptoms and, with a lifelong interest in the history of the field,11 de Morsier attached names to the resulting syndromic entities, outlined in Table I. The main part of his 1936 work was a syndrome he named after Hermann Zingerle (1870-1935), an Austrian neurologist from Graz with an interest in motor automatisms. This consisted of visual hallucinations in the context of oculogyric crisis, persistent movement disorder, and central vestibular symptoms attributed to lesions of the parietal lobe. The modern equivalent would perhaps be the positive visual phenomena (typically Inhibitors,research,lifescience,medical intensification of visual patterns and letters) associated Inhibitors,research,lifescience,medical with neuroleptic-induced oculogyric crises.12,13 De Morsier also honoured de Clérambault with a syndrome – not erotomania but the chronic hallucinatory psychosis which had helped derive the theory of mental automatisms. L’Hermitte was honoured with the peduncular syndrome, although

de Morsier argued that the important lesion was in the pulvinar, not the cerebral peduncles. Other visual hallucinatory syndromes he described were not named. One concerned the visual hallucinations Histone demethylase found in delirium tremens that had been studied by his friend and colleague in Geneva, Ferdinand Morel. These hallucinations had the unusual property of being precipitated when one eye was covered, typically the eye with better acuity, and were located in the central 10 to 15 degrees of the visual field. Neurodegenerative, vascular, neoplastic, toxic, traumatic, inflammatory, and epileptic etiologies were also included. Although incomplete, much of de Morsier’s classification remains relevant today, some of his notable omissions conditions that had yet to be described.