Research data from University of Tubingen update understanding of agnosia
2009 JUL 14 - (NewsRx.com) -- "The influential model on visual information processing by Milner and Goodale (1995) has suggested a dissociation between action-and perception-related processing in a dorsal versus ventral stream projection. It was inspired substantially by the observation of a double dissociation of disturbed visual action versus perception in patients with optic ataxia on the one hand and patients with visual form agnosia (VFA) on the other," investigators in Tubingen, Germany report. "Unfortunately, almost all cases with VFA reported so far suffered from inhalational intoxication, the majority with carbon monoxide (CO). Since CO induces a diffuse and widespread pattern of neuronal and white matter damage throughout the whole brain, precise conclusions from these patients with VFA on the selective role of ventral stream structures for shape and orientation perception were difficult. Here, we report patient J.S., who demonstrated VFA after a well circumscribed brain lesion due to stroke etiology. Like the famous patient D. F. with VFA after CO intoxication studied by Milner, Goodale, and coworkers (Goodale et al., 1991, 1994; Milner et al., 1991; Servos et al., 1995; Mon-Williams et al., 2001a,b; Wann et al., 2001; Westwood et al., 2002; McIntosh et al., 2004; Schenk and Milner, 2006), J.S. showed an obvious dissociation between disturbed visual perception of shape and orientation information on the one side and preserved visuomotor abilities based on the same information on the other. In both hemispheres, damage primarily affected the fusiform and the lingual gyri as well as the adjacent posterior cingulate gyrus," wrote H.O. Karnath and colleagues, University of Tubingen. The researchers concluded: "These medial structures of the ventral occipitotemporal cortex are integral for the normal flow of shape and of contour information into the ventral stream system allowing to recognize objects.." Karnath and colleagues published their study in the Journal of Neuroscience (The Anatomy of Object Recognition-Visual Form Agnosia Caused by Medial Occipitotemporal Stroke. Journal of Neuroscience, 2009;29(18):5854-5862). For additional information, contact H.O. Karnath, University of Tubingen, Center Neurology, Hertie Institute Clinic Brain Research, Sect Neuropsychol, Hoppe Seyler Str 3, D-72076 Tubingen, Germany. The publisher of the Journal of Neuroscience can be contacted at: Society Neuroscience, 11 Dupont Circle, NW, Ste. 500, Washington, DC 20036, USA. Keywords: Germany, Tubingen, Agnosia, Anatomy, Ataxia, Neuroscience, University of Tubingen. This article was prepared by Life Science Weekly editors from staff and other reports. Copyright 2009, Life Science Weekly via NewsRx.com.
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