title: Further evidence for a reversed crossing of foveal projections in schizophrenic vulnerability.
abstract: Further evidence in support of the thesis developed in a previous article published in Medical Hypotheses (Sept. 2000) proposing that schizophrenic vulnerability might consist of the temporal instead of the nasal foveal projections crossing over in the chiasma opticum has been provided by an experiment in which pinholes are used to isolate foveally stimulated from peripherally stimulated vergence. By shifting the pinholes inwards or outwards a dilemma is created regarding the fusion of the edges of the two pinholes or of a single diode light seen at the inner or outer edges of the pinholes. It was revealed that schizophrenic patients never solved the dilemma in favour of what was represented on the temporal foveal halves while this was always the case in the control group. At best, the patients fusioned neither the diode light nor the pinhole edges but saw both double. An explanation is given as to how this disturbance might be based on the interchange of nasal and temporal foveal projections and might lead to the dissociation of the visual goals of the two eyes, as shown in a previous test. The cause of markers of schizophrenic vulnerability mentioned in literature, in particular saccaded SPEM, P50 response and hyperdopaminergia, is related to such an interchange and suggestions are made for further experiments. Finally, the difficulty of schizophrenic patients to distinguish between reality and illusion is attributed to a disconnection of spatial and object perception.
authors.affiliation: Licencié ès lettres Sarbonne.
authors.forename: H
authors.initials: H
authors.lastname: Korn
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000328:Adult; D002648:Child; D003290:Convergence, Ocular / Q000502:physiology*; D004172:Diplopia / Q000209:etiology* / Q000473:pathology; D004198:Disease Susceptibility; D004292:Dominance, Cerebral; D004644:Emotions; D005584:Fovea Centralis / Q000473:pathology*; D006212:Hallucinations / Q000209:etiology; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008959:Models, Neurological; D008960:Models, Psychological; D009897:Optic Chiasm / Q000473:pathology*; D009900:Optic Nerve / Q000473:pathology*; D011597:Psychomotor Performance; D011930:Reaction Time; D012438:Saccades; D012559:Schizophrenia / Q000209:etiology / Q000473:pathology*; D012565:Schizophrenic Psychology; D013028:Space Perception / Q000502:physiology*; D035502:Trust; D015357:Vision Disparity; D015348:Vision, Binocular / Q000502:physiology; D014794:Visual Fields; D014795:Visual Pathways / Q000473:pathology