Manatee cerebral cortex: cytoarchitecture of the caudal region in Trichechus manatus latirostris.
In several brains of the Florida manatee, Trichechus manatus latirostris, the architecture of caudal regions of cerebral cortex was examined in order to complete a map of cortical areas in the brain of this unique herbivore. Through observation of sections stained for Nissl substance, myelinated axons, acetylcholinesterase and cytochrome oxidase, we have identified 11 new cortical areas based on qualitative cytoarchitectural appearance and measurements of laminar thicknesses, for a total of 24 such cortical areas in manatee cerebral cortex. Some areas exhibit poorly differentiated laminae while in others there are 6 clearly demarcated layers, often with sublaminar organization. Some previously identified areas were found to extend into the region caudal to the vertically oriented lateral fissure. As in other mammalian brains, cortical areas in manatees are organized in concentric rings of allocortex, mesocortex, and isocortex. Putative functional roles have been assigned to most of the identified areas based on location, architecture, behavioral and anatomical considerations, and extrapolation from other taxa in which functional mapping has been done.
Marshall
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CD
Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610.
Reep
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RL
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D005075:Biological Evolution; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D006652:Histological Techniques; D008322:Mammals / Q000033:anatomy & histology*; D009474:Neurons / Q000648:ultrastructure; D010802:Phylogeny; D013045:Species Specificity