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Anatomical evidence for segregated processing streams in the cat’s visual cortex Boyd, Jamie D.
Abstract
Studies in primates suggest the existence of at least three separate systems operating in parallel and specialized to process information about: 1) shape; 2) colour; and 3) motion. In visual cortex, these systems are segregated into either the “blobs” staining densely for cytochrome oxidase (CO), or the less densely staining interbiobs. Recent reports of CO blobs in the cat led to this investigation to determine whether CO blobs in this species also act to segregate inputs and outputs. LGN inputs to cat Vi arise from three classes of cells, known as X, Y, and W cells. W cell input was found in different layers of areas 17 and 18 than the X and Y cell input and was localized to CO blobs but not interblobs. The Y cell input from layer C was also found to be confined to the blobs. Area 17 has five major output pathways; to areas 18, 19, 20a, 21a, and the posterior medial lateral suprasylvian area (PMLS). In areas 17 and 18, PMLS-projecting cells were clustered within the CO blobs. Labeling from injections in PMLS was also observed in other cortical areas, and was always clustered, most notably in area 19, where clusters of labeled cells were much wider than in other areas, and often elongated in a direction perpendicular to the 18/19 border. Large injections of tracers into area 19 labeled both blobs and interblobs in areas 17 and 18 while small injections often labeled either only blobs, or only interblobs. Labeling of the callosal pathway, while dense and uniform at the 17/18 border, showed, at the edges of the labeling pattern in areas 17 and 18, regular fluctuations of labeling density that aligned with the CO blobs. Together, these results provide the first demonstration of segregated visual processing streams in a non-primate species. Such an organization may be a general characteristic of mammalian visual cortical organization and not a primate specialization, as was once thought. Knowledge of these pathways in cats, a frequently used system for many developmental and physiological studies, should prove valuable.
Item Metadata
Title |
Anatomical evidence for segregated processing streams in the cat’s visual cortex
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1995
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Description |
Studies in primates suggest the existence of at least three separate systems operating in parallel
and specialized to process information about: 1) shape; 2) colour; and 3) motion. In visual cortex,
these systems are segregated into either the “blobs” staining densely for cytochrome oxidase (CO),
or the less densely staining interbiobs. Recent reports of CO blobs in the cat led to this
investigation to determine whether CO blobs in this species also act to segregate inputs and
outputs.
LGN inputs to cat Vi arise from three classes of cells, known as X, Y, and W cells. W cell
input was found in different layers of areas 17 and 18 than the X and Y cell input and was localized
to CO blobs but not interblobs. The Y cell input from layer C was also found to be confined to the
blobs.
Area 17 has five major output pathways; to areas 18, 19, 20a, 21a, and the posterior medial
lateral suprasylvian area (PMLS). In areas 17 and 18, PMLS-projecting cells were clustered
within the CO blobs. Labeling from injections in PMLS was also observed in other cortical areas,
and was always clustered, most notably in area 19, where clusters of labeled cells were much
wider than in other areas, and often elongated in a direction perpendicular to the 18/19 border.
Large injections of tracers into area 19 labeled both blobs and interblobs in areas 17 and 18
while small injections often labeled either only blobs, or only interblobs.
Labeling of the callosal pathway, while dense and uniform at the 17/18 border, showed, at the
edges of the labeling pattern in areas 17 and 18, regular fluctuations of labeling density that aligned
with the CO blobs.
Together, these results provide the first demonstration of segregated visual processing streams
in a non-primate species. Such an organization may be a general characteristic of mammalian
visual cortical organization and not a primate specialization, as was once thought. Knowledge of
these pathways in cats, a frequently used system for many developmental and physiological
studies, should prove valuable.
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Extent |
9186029 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-06-04
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0088825
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1995-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.