Total number and volume of Von Economo neurons in the cerebral cortex of cetaceans.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Butti, Camilla; Sherwood, Chet C; Hakeem, Atiya Y; Allman, John M; Hof, Patrick R
Year of Publication: 2009
Journal: J Comp Neurol
Volume: 515
Issue: 2
Pagination: 243-59
Date Published: 2009 Jul 10
Publication Language: eng
ISSN: 1096-9861
Keywords: Animals, Body Weight, Brain Mapping, Cell Count, Cerebral Cortex, Dolphins, Neurons, Organ Size, Pyramidal Cells, Species Specificity, Whales

Von Economo neurons (VENs) are a type of large, layer V spindle-shaped neurons that were previously described in humans, great apes, elephants, and some large-brained cetaceans. Here we report the presence of Von Economo neurons in the anterior cingulate (ACC), anterior insular (AI), and frontopolar (FP) cortices of small odontocetes, including the bottlenose dolphin (Tursiops truncatus), the Risso's dolphin (Grampus griseus), and the beluga whale (Delphinapterus leucas). The total number and volume of VENs and the volume of neighboring layer V pyramidal neurons and layer VI fusiform neurons were obtained by using a design-based stereologic approach. Two humpback whale (Megaptera novaeangliae) brains were investigated for comparative purposes as representatives of the suborder Mysticeti. Our results show that the distribution of VENs in these cetacean species is comparable to that reported in humans, great apes, and elephants. The number of VENs in these cetaceans is also comparable to data available from great apes, and stereologic estimates indicate that VEN volume follows in these cetacean species a pattern similar to that in hominids, the VENs being larger than neighboring layer V pyramidal cells and conspicuously larger than fusiform neurons of layer VI. The fact that VENs are found in species representative of both cetacean suborders in addition to hominids and elephants suggests that these particular neurons have appeared convergently in phylogenetically unrelated groups of mammals possibly under the influence of comparable selective pressures that influenced specifically the evolution of cortical domains involved in complex cognitive and social/emotional processes.

DOI: 10.1002/cne.22055
Alternate Journal: J. Comp. Neurol.