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Distribution of corticotectal cells in macaque.
T M Lock1, J S Baizer, D B Bender
1Department of Pediatrics, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
Experimental Brain Research
|July 10, 2003
Summary
The corticotectal system has two divisions: a visual pathway projecting to superficial superior colliculus layers and a visuomotor pathway targeting deep layers. This clarifies the functional organization of visual processing and motor control pathways.
Area of Science:
- Neuroscience
- Visual System Research
- Cortical Connectivity
Background:
- The superior colliculus (SC) has distinct superficial (visual) and deep (visuomotor) layers.
- It is unclear if the cortical inputs to the SC mirror this functional division.
Purpose of the Study:
- To investigate whether the corticotectal system comprises two functional divisions: visual and visuomotor.
- To map the cortical projections to the superficial and deep compartments of the superior colliculus.
Main Methods:
- Injections of retrograde tracers into different SC layers and representations (upper/lower quadrants) in non-human primates.
- Analysis of labeled cells in various cortical visual and prefrontal/parietal areas.
Main Results:
- Cortical inputs to the SC are largely segregated.
- A visual component, originating from striate cortex (V1) and early visual areas (V2, V3, MT), projects to superficial SC layers.
- A visuomotor component, from higher visual, prefrontal, and parietal areas, projects to deep SC layers.
Conclusions:
- The corticotectal system is organized into two largely non-overlapping functional divisions.
- The visual division processes visual information for superficial SC layers.
- The visuomotor division integrates information for sensorimotor transformations in deep SC layers.