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Regional brain morphometry and lissencephaly in the Sirenia

January 1, 1990

Neuroanatomical structure was examined in the brains of West Indian manatees (Trichechus manatus) using computer-based morphometric methods. Although manatees have a small relative brain size, volume estimates of the major brain regions indicate that the telencephalon comprises 71% of totalbrain volume and is 90% cerebral cortex. These values are comparable to those seen among a diversity of taxa having large relative brain size, including many primates. Manatee brains also exhibit well-defined cortical lamination. The measured gyration index (an index of cortical folding) was 1.06, representing a highly lissencephalic condition. These findings demonstrate that small relative brain size and lissencephaly do not constrain the elaboration of internal brain structures. The marked lissencephalic condition is unusual for brains of this absolute size range, and may be related to the thickness of the cortical gray matter and underlying white matter.

Publication Year 1990
Title Regional brain morphometry and lissencephaly in the Sirenia
DOI 10.1159/000115866
Authors Roger L. Reep, Thomas J. O'Shea
Publication Type Article
Publication Subtype Journal Article
Series Title Brain, Behavior and Evolution
Index ID 1008566
Record Source USGS Publications Warehouse
USGS Organization Florida Integrated Science Center