Different early rearing experiences have long‐term effects on cortical organization in captive chimpanzees (Pan troglodytes)

Abstract

Consequences of rearing history in chimpanzees (Pan troglodytes) have been explored in relation to behavioral abnormalities and cognition, however, little is known about the effects of rearing conditions on anatomical brain development. Human studies have revealed that experiences of maltreatment and neglect during infancy and childhood can have detrimental effects on brain development and cognition. In this study, we evaluated the effects of early rearing experience on brain morphology in 92 captive chimpanzees (ages 11-43) who were either reared by their mothers (n = 46) or in a nursery (n = 46) with age-group peers. Magnetic resonance brain images were analyzed with a processing program (BrainVISA) that extracts cortical sulci. We obtained various measurements from 11 sulci located throughout the brain, as well as whole brain gyrification and white and grey matter volumes. We found that mother-reared chimpanzees have greater global white-to-grey matter volume, more cortical folding and thinner grey matter within the cortical folds than nursery-reared animals. The findings reported here are the first to demonstrate that differences in early rearing conditions have significant consequences on brain morphology in chimpanzees and suggests potential differences in the development of white matter expansion and myelination.

Etiology of Triarchic Psychopathy Dimensions in Chimpanzees (Pan troglodytes)

“…As described previously (i.e., Bogart et al, 2014), although offspring in each of the two early rearing groups were not entirely heterogeneous, the degree of genetic diversity was comparable between them. That is, early rearing differences in our sample of chimpanzees were not attributable to genetic differences between offspring born to mothers who were capable of raising them versus offspring born to mothers who were unable to provide adequate care (Bogart et al, 2014). Nonetheless, it will be important in future research to work toward identifying nuances of alternative early-rearing conditions that give rise to the observed differences in heritability of psychopathy subdimensions.…”

“…The data for these subjects are therefore ex post facto and opportunistic; indeed, we capitalized on the fact that some of the chimpanzees received different rearing experiences in order to evaluate whether this might have long-term consequences on personality development. Importantly, as described previously (Bogart et al, 2014), based on the composition of the rearing groups, potential rearing differences are likely not conflated with familial environment. Specifically, the genetic diversity within each group was comparable.…”

Primate Brain Anatomy: New Volumetric MRI Measurements for Neuroanatomical Studies

“…Nevertheless, these studies have made substantial contributions to the Stephan et al dataset, particu-larly in the addition of data on multiple individuals for certain primate species, in particular the great apes. Such additions have led to, e.g., reassessment of the assumption that the ratio of the different brain components is constant between conspecifics and has contributed to a greater understanding of intraspecific variation in brain anatomy in primates [Bogart et al, 2014].…”

Neuroplasticity and MRI: A perfect match

“…Another argument illustrating the vital importance of early life experiences can be found in adverse rearing conditions or early traumatic experiences. Bogart and colleagues (2014) investigated the consequences of different rearing conditions of brain morphology and found profound differences in global white-to-grey matter volume ratio, depth of cortical folds and grey matter thickness when comparing mother-and nurseryreared chimpanzees (Bogart, Bennett et al 2014). A similar study has been performed in the clinic, studying the effects of childhood emotional maltreatment on brain structure.…”