| Detection and discrimination of first- and second-order motion in patients with unilateral brain damage. | |
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MedLine Citation:
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PMID: 8987802 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The present investigation explored the extent to which extrastriate cortex is necessary for various aspects of motion processing and whether the processing of first-order (Fourier) and second-order (non-Fourier) motion involves the same extrastriate cortical regions. Orientation, direction, and speed discrimination thresholds were measured in 21 patients with unilateral damage to the lateral occipital, temporal, or posterior parietal cortex. Their results were compared with those of 14 age-matched control subjects. The stimuli were static random-dot noise patterns, the luminance of which (first-order) or contrast (second-order) was modulated by a drifting sinusoid. Each image was presented at an eccentricity of 5.6 deg in one of the four visual quadrants. The contrasts required to identify orientation and direction were measured in a forced-choice paradigm for three speeds (1.5, 3, and 6 deg/sec). Speed discrimination performance was measured for stimuli presented simultaneously in two of the four quadrants. The results indicate the following: (1) orientation thresholds were increased only slightly in the patients; (2) direction thresholds were modestly elevated, and this effect was more pronounced for second-order stimuli than for first-order stimuli; (3) speed discrimination thresholds were elevated significantly in the patients with lesions in the region bordering superior-temporal and lateral-occipital cortex; and (4) speed discrimination thresholds for first-order stimuli were more elevated than those for second-order stimuli. The results suggest that there is substantial overlap in the cortical areas involved in first- and second-order speed discrimination. |
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Authors:
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M W Greenlee; A T Smith |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of neuroscience : the official journal of the Society for Neuroscience Volume: 17 ISSN: 0270-6474 ISO Abbreviation: J. Neurosci. Publication Date: 1997 Jan |
Date Detail:
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Created Date: 1997-11-28 Completed Date: 1997-11-28 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8102140 Medline TA: J Neurosci Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 804-18 Citation Subset: IM; S |
Affiliation:
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Neurologische Universitätsklinik, Freiburg, Germany. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Brain Damage, Chronic / etiology, physiopathology* Brain Neoplasms / complications Cerebral Cortex / physiopathology* Cerebrovascular Disorders / complications Discrimination (Psychology) / physiology* Dominance, Cerebral Female Humans Male Middle Aged Motion Perception / physiology* Occipital Lobe / injuries, physiopathology Parietal Lobe / injuries, physiopathology Postoperative Complications Signal Detection, Psychological / physiology* Temporal Lobe / injuries, physiopathology Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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