It has come to our attention that some of the data on the cellular composition of the brain of artiodactyls, presented in Table 1 of Kazu et al. (2014) and used in this review, needed minor corrections, which were published in a Corrigendum to that paper.
While those corrections do not at all modify the conclusions of the present paper, some of the power exponents reported here were influenced in minor, non-significant ways. We provide those corrected power exponents below.
p. 4, Figure 2, top right—The mass of each brain structure varies as a similar, shared power function of the number of non-neuronal (other) cells in the structure of exponent 1.050 ± 0.018 (p < 0.0001).
p. 6, Figure 3, top: Mass of the cerebral cortex increases with number of neurons raised to an exponent of 1.694 ± 0.048 across non-primates.
p. 6, Figure 3, bottom: Neuronal density in the cerebral cortex decreases with number of neurons raised to an exponent of −0.693 ± 0.048 (p < 0.0001).
p. 9, Figure 4: In non-primates, non-eulipotyphlans, cerebellar mass increases with number of neurons raised to an exponent of 1.283 ± 0.035 (p < 0.0001) and cerebellar neuronal density scales with number of neurons raised to an exponent of −0.282 ± 0.035 (p < 0.0001).
Figure 7:
A—Neuronal density in the cerebral cortex scales with neuronal density in the rest of brain raised to an exponent of 0.876 ± 0.041, p < 0.0001 (excludes primates).
B—Neuronal density in the cerebellum scales with neuronal density in the rest of brain raised to an exponent of 0.442 ± 0.049, p < 0.0001 (excludes primates and eulipotyphlans).
C—Neuronal density in the olfactory bulb scales with neuronal density in the rest of brain raised to an exponent of 0.994 ± 0.118, p < 0.0001 (excludes primates and eulipotyphlans).
D—Neuronal density in the olfactory bulb scales with neuronal density in the cerebral cortex raised to an exponent of 1.139 ± 0.113, p < 0.0001 (excludes primates and eulipotyphlans).
E—Neuronal density in the cerebellum scales with neuronal density in the cerebral cortex raised to an exponent of 0.516 ± 0.041, p < 0.0001 (excludes primates and eulipotyphlans).
F—Neuronal density in the olfactory bulb scales with neuronal density in the cerebellum raised to an exponent of 1.706 ± 0.161, p < 0.0001 (includes all clades).
p. 12, Figure 8A—Artiodactyls gain neurons in the cerebral cortex faster than they gain neurons in the rest of brain, as a power function of exponent 1.552 ± 0.056, p = 0.0013, r2 = 0.997 (excludes the giraffe).
p. 12, Figure 8B—Artiodactyls gain neurons in the cerebellum faster than they gain neurons in the rest of brain, as a power function of exponent 1.737 ± 0.304, p = 0.0107, r2 = 0.916.
p. 14, Figure 9B—The number of neurons in the cerebellum varies as a power function of the number of neurons in the cerebral cortex with an exponent of 0.922 ± 0.110, p = 0.0036, across artiodactyls. The relationship for the ensemble of clades can also be fit with a linear function of slope 4.16 (p < 0.0001, r2 = 0.985).
p. 15, Figure 10A—Artiodactyls have on average 7.35 ± 1.24 neurons in the cerebral cortex to every neuron in the rest of brain. This ratio increases as a power function of the number of neurons in the rest of brain with an exponent of 0.904 ± 0.132 (p = 0.0135, r2 = 0.902).
p. 16, Figure 10B—Artiodactyls have a ratio between numbers of neurons in the cerebellum and in the rest of brain of 38.32 ± 6.19.
p. 17—Artiodactyls have an average ratio of neurons in the cerebellum relative to the cerebral cortex of 5.28 ± 0.31.
p. 21, Figure 13:
A—The mass of the cerebral cortex increases across non-primates with the mass of the rest of brain raised to an exponent of 1.155 ± 0.027, p < 0.0001.
B—The mass of the cerebellum increases across non-primates with the mass of the rest of brain raised to an exponent of 1.054 ± 0.019, p < 0.0001.
C—The mass of the olfactory bulb increases across non-primates with the mass of the rest of brain raised to an exponent of 0.812 ± 0.043, p < 0.0001.
D—The relative mass of the cerebral cortex increases across all species in correlation with brain mass with a Spearman correlation r2 = 0.7840, p < 0.0001.
E—The relative mass of the cerebellum varies across all species in correlation with brain mass with a Spearman correlation r2 = −0.5270, p = 0.0008.
F—The relative mass of the rest of brain varies across all species in correlation with brain mass with a Spearman correlation r2 = −0.7994, p < 0.0001.
p. 21, Figure 14—The cerebral cortex of artiodactyls gains mass as a function of the number of neurons in the rest of brain with exponent 2.759 ± 0.145, p = 0.0028. The cerebellum of artiodactyls gains mass as a function of the number of neurons in the rest of brain with exponent 2.142 ± 0.492, p = 0.0489.
p. 24, Figure S17—In artiodactyls, cerebral cortical mass increases as a power function of body mass with exponent 0.589 ± 0.028, p = 0.0023; rest of brain mass increases as a power function of body mass with exponent 0.378 ± 0.056, p = 0.0215; the number of neurons in the cerebral cortex scales with body mass raised to an exponent of 0.454 ± 0.107, p = 0.0511; and the number of neurons in the rest of brain scales with body mass raised to an exponent of 0.227 ± 0.027, p = 0.0136.
Conflict of interest statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest