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. 2014 Feb 17;8:5. doi: 10.3389/fnana.2014.00005

Figure 4.

Figure 4

Cellular scaling rules for afrotherian brain structures. (A) Average mass of each brain structure is plotted for each afrotherian species as a function of its total number of other (non-neuronal) cells. Power functions are plotted separately for each structure, and have similar exponents of 1.179 ± 0.091 (cerebral cortex without hippocampus, open circles), 1.182 ± 0.109 (cerebral cortex with hippocampus, filled circles), 1.112 ± 0.214 (cerebellum, filled squares), 0.862 ± 0.239 (hippocampus, open squares), and 1.119 ± 0.168 (rest of brain, triangles). (B–F) Average mass of each brain structure plotted for each species as a function of its total number of neurons. (B) cerebral cortex including hippocampus; (C) hippocampus; (D) cerebral cortex without hippocampus; (E) cerebellum; (F) rest of brain. Afrotherian species shown in black, primates in red, scandentia in gray, glires in green, and eulipotyphlans in orange. Data from Herculano-Houzel et al. (2006, 2007); Herculano-Houzel et al. (2011); Azevedo et al. (2009); Sarko et al. (2009); Gabi et al. (2010). Power functions for each group are plotted. Exponents for structure mass × numbers of neurons are: Cerebral cortex with hippocampus (B), 1.540 ± 0.199 (afrotherians), 1.699 ± 0.096 (Glires), 1.598 ± 0.618 (eulipotyphlans), 1.087 ± 0.074 (primates). Hippocampus (C), 1.121 ± 0.312 (afrotherians), 1.041 ± 0.422 (eulipotyphlans). Cerebral cortex without hippocampus (D), 1.497 ± 0.157 (afrotherians), 1.546 ± 0.575 (eulipotyphlans). Cerebellum (E), 1.316 ± 0.130 (afrotherians), 1.305 ± 0.072 (Glires), 0.976 ± 0.036 (eulipotyphlans), 1.028 ± 0.084 (primates). Rest of brain (F), 1.305 ± 0.246 (afrotherians), 1.297 ± 0.476 (eulipotyphlans), 1.198 ± 0.112 (primates), 1.533 ± 0.203 (Glires).