title: Brain structure variation in great apes, with attention to the mountain gorilla (Gorilla beringei beringei).
abstract: This report presents data regarding the brain structure of mountain gorillas (Gorilla beringei beringei) in comparison with other great apes. Magnetic resonance (MR) images of three mountain gorilla brains were obtained with a 3T scanner, and the volume of major neuroanatomical structures (neocortical gray matter, hippocampus, thalamus, striatum, and cerebellum) was measured. These data were included with our existing database that includes 23 chimpanzees, three western lowland gorillas, and six orangutans. We defined a multidimensional space by calculating the principal components (PCs) from the correlation matrix of brain structure fractions in the well-represented sample of chimpanzees. We then plotted data from all of the taxa in this space to examine phyletic variation in neural organization. Most of the variance in mountain gorillas, as well as other great apes, was contained within the chimpanzee range along the first two PCs, which accounted for 61.73% of the total variance. Thus, the majority of interspecific variation in brain structure observed among these ape taxa was no greater than the within-species variation seen in chimpanzees. The loadings on PCs indicated that the brain structure of great apes differs among taxa mostly in the relative sizes of the striatum, cerebellum, and hippocampus. These findings suggest possible functional differences among taxa in terms of neural adaptations for ecological and locomotor capacities. Importantly, these results fill a critical gap in current knowledge regarding great ape neuroanatomical diversity.
authors.affiliation: Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA. csherwoo@kent.edu
authors.forename: Chet C
authors.initials: CC
authors.lastname: Sherwood
authors.forename: Michael R
authors.initials: MR
authors.lastname: Cranfield
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Mehlman
authors.forename: Alecia A
authors.initials: AA
authors.lastname: Lilly
authors.forename: Jo Anne L
authors.initials: JA
authors.lastname: Garbe
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Whittier
authors.forename: Felicia B
authors.initials: FB
authors.lastname: Nutter
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Rein
authors.forename: Harlan J
authors.initials: HJ
authors.lastname: Bruner
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Holloway
authors.forename: Cheuk Y
authors.initials: CY
authors.lastname: Tang
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Naidich
authors.forename: Bradley N
authors.initials: BN
authors.lastname: Delman
authors.forename: H Dieter
authors.initials: HD
authors.lastname: Steklis
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Erwin
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Hof
mesh_terms: D000818:Animals; D001344:Autopsy / Q000662:veterinary; D001699:Biometry; D001921:Brain / Q000033:anatomy & histology*; D016208:Databases, Factual; D005260:Female; D006071:Gorilla gorilla / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D002679:Pan troglodytes / Q000033:anatomy & histology; D011148:Pongo pygmaeus / Q000033:anatomy & histology