The more you know the less you can tell: inhibitory effects of visuo-semantic activation on modality specific visual misnaming.
WH, a 77-years old right-handed psychoanalyst, displayed modality specific visual misnaming as a sequel of an embolic stroke in the left posterior cerebral artery. WH's errors in visual object naming consisted mainly of semantic paraphasias and perseverations. His verbalizations during testing sometimes manifested a conflict between correct responses and perseverations. Analysis of the stream of information from visual perception via semantics to phonology suggested incomplete access from vision to semantics as the source of errors. The disconnection did not affect verbo-visual matching, though he was unable to reject names that did not correspond to visual stimuli. Action naming was relatively spared, but naming of pictures of actions with objects was worse than naming of pictures of intransitive actions. Tactile naming worsened with simultaneous vision of objects. In visual object naming the error rate increased with increasing familiarity of objects. We propose that an interaction of excitation and inhibition within a single semantic system can explain the clinical phenomena of modality specific visual misnaming.
Goldenberg
G
G
Neuropsychological Department, Bogenhausen Hospital, Munich, Germany. Georg.Goldenberg@lrz.tum.de
Karlbauer
F
F
D000368:Aged; D000377:Agnosia / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D002536:Cerebral Arteries / Q000473:pathology; D002544:Cerebral Infarction / Q000503:physiopathology; D004410:Dyslexia / Q000503:physiopathology; D006801:Humans; D008297:Male; D009433:Neural Inhibition; D012660:Semantics; D013060:Speech / Q000502:physiology; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology