Biomaterial Database

Functional segregation of color and motion processing in the human visual cortex: clinical evidence. 1994

L M Vaina

Department of Biomedical Engineering, Boston University, Massachusetts 02215.

Anatomical and physiological investigations indicate two major distinct functional streams within the extrastriate visual cortex of the macaque monkey, and behavioral observations suggest that the ventral (occipitotemporal) pathway is the cornerstone for object recognition whereas the dorsal (occipitoparietal) pathway is primarily involved in visuospatial perception and visuomotor performance. In the context of this dichotomy we conducted a psychophysical and neuropsychological study of visual perceptual abilities in two stroke patients, each with lesions involving several extrastriate areas. Magnetic resonance imaging demonstrated bilateral lesions; in one patient (E.W.) the lesion involves the ventral medial portions of the occipital and temporal lobes, and in the other (A.F.) the lesion involves dorsally the occipital-parietal area, including the region of the temporal-parietal-occipital junction. E.W. suffers from achromatopsia of central origin, prosopagnosia, visual agnosia, and alexia without agraphia. His depth and motion perception, including recognition of moving objects, are normal. He has superior visual field loss bilaterally, and slightly impaired acuity, and complains that the world appears in a deep twilight even on a sunny day. In contrast, A.F. shows specific deficits of stereopsis, spatial localization, and several aspects of motion perception. He is also impaired at recognizing objects presented from unconventional views, but recognition of prototypical views of objects, and color and form discrimination are normal, as is his ability to recognize faces. The anatomical characteristics of the lesions of these two patients permit a direct experimental comparison of the effects of lesions confined to the parietal or temporal pathways. E.W.'s and A.F.'s performance on the psychophysical and neuropsychological tasks discussed here supports the functional distinction between a dorsal and a ventral extrastriate system but additionally suggests the existence of a pathway involved in identification-from-motion that is separate from both the dorsal early motion/spatial analysis pathway and the ventral color/static-form pathway.

UI	MeSH Term	Description	Entries
D008279	Magnetic Resonance Imaging	Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.	Chemical Shift Imaging,MR Tomography,MRI Scans,MRI, Functional,Magnetic Resonance Image,Magnetic Resonance Imaging, Functional,Magnetization Transfer Contrast Imaging,NMR Imaging,NMR Tomography,Tomography, NMR,Tomography, Proton Spin,fMRI,Functional Magnetic Resonance Imaging,Imaging, Chemical Shift,Proton Spin Tomography,Spin Echo Imaging,Steady-State Free Precession MRI,Tomography, MR,Zeugmatography,Chemical Shift Imagings,Echo Imaging, Spin,Echo Imagings, Spin,Functional MRI,Functional MRIs,Image, Magnetic Resonance,Imaging, Magnetic Resonance,Imaging, NMR,Imaging, Spin Echo,Imagings, Chemical Shift,Imagings, Spin Echo,MRI Scan,MRIs, Functional,Magnetic Resonance Images,Resonance Image, Magnetic,Scan, MRI,Scans, MRI,Shift Imaging, Chemical,Shift Imagings, Chemical,Spin Echo Imagings,Steady State Free Precession MRI
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009039	Motion Perception	The real or apparent movement of objects through the visual field.	Movement Perception,Perception, Motion,Perception, Movement
D002561	Cerebrovascular Disorders	A spectrum of pathological conditions of impaired blood flow in the brain. They can involve vessels (ARTERIES or VEINS) in the CEREBRUM, the CEREBELLUM, and the BRAIN STEM. Major categories include INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; BRAIN ISCHEMIA; CEREBRAL HEMORRHAGE; and others.	Brain Vascular Disorders,Intracranial Vascular Disorders,Vascular Diseases, Intracranial,Cerebrovascular Diseases,Cerebrovascular Insufficiency,Cerebrovascular Occlusion,Brain Vascular Disorder,Cerebrovascular Disease,Cerebrovascular Disorder,Cerebrovascular Insufficiencies,Cerebrovascular Occlusions,Disease, Cerebrovascular,Diseases, Cerebrovascular,Insufficiencies, Cerebrovascular,Insufficiency, Cerebrovascular,Intracranial Vascular Disease,Intracranial Vascular Diseases,Intracranial Vascular Disorder,Occlusion, Cerebrovascular,Occlusions, Cerebrovascular,Vascular Disease, Intracranial,Vascular Disorder, Brain,Vascular Disorder, Intracranial,Vascular Disorders, Brain,Vascular Disorders, Intracranial
D003072	Cognition Disorders	Disorders characterized by disturbances in mental processes related to learning, thinking, reasoning, and judgment.	Overinclusion,Disorder, Cognition,Disorders, Cognition
D003118	Color Perception	Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.	Color Perceptions,Perception, Color,Perceptions, Color
D005133	Eye Movements	Voluntary or reflex-controlled movements of the eye.	Eye Movement,Movement, Eye,Movements, Eye
D005145	Face	The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.	Faces
D005556	Form Perception	The sensory discrimination of a pattern, shape, or outline.	Contour Perception,Contour Perceptions,Form Perceptions,Perception, Contour,Perception, Form,Perceptions, Contour,Perceptions, Form