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McCormack KM, Howell BR, Higgins M, Bramlett S, Guzman D, Morin EL, Villongco C, Liu Y, Meyer J, Sanchez MM. The developmental consequences of early adverse care on infant macaques: A cross-fostering study. Psychoneuroendocrinology 2022; 146:105947. [PMID: 36242820 DOI: 10.1016/j.psyneuen.2022.105947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022]
Abstract
Early life adversity/stress (ELA/ELS), particularly adverse caregiving experiences such as child maltreatment (MALT), is a main risk factor for psychopathology, including psychiatric disorders such as anxiety, depression, ADHD, and substance abuse. Yet how these alterations unfold during development and the underlying mechanisms remain poorly understood, as it is difficult to prospectively and longitudinally study early developmental phases in humans, and nearly impossible to disentangle postnatal caregiving effects from heritable traits. This study examined the specific effects of "nurture" (maternal care) versus "nature" (heritable, biological maternal factors) on nonhuman primate infant socioemotional, stress neuroendocrine, and physical development. For this we used a translational and naturalistic macaque model of infant maltreatment by the mother with randomized assignment at birth to either mothers with a history of maltreating their infants (MALT group, n = 22) or to competent mothers (Control group, n = 20). Over the first 6 months of life (roughly equivalent to 2 years in humans), we examined the development of the mother-infant relationship, as well as infants' social behavior and emotional reactivity. In parallel, we assessed hypothalamic-pituitary-adrenal (HPA) axis function longitudinally, using measures of hair cortisol accumulation, and basal morning plasma cortisol. We identified broad impairments in maternal care exhibited by MALT foster mothers, beyond maltreatment (physical abuse, rejection) events, suggesting that MALT foster mothers provide an overall lower quality of care to their infants compared to Controls. MALT infants exhibited alterations in their initiations and breaks of proximity towards their mothers, as well as heightened emotional reactivity in comparison to Controls. Most striking are the HPA axis findings, with MALT infants showing higher levels of plasma cortisol across the first 6 postnatal months as well as higher hair cortisol accumulation from birth through month 6 (a signature of chronic stress) than Controls. No caregiving effects were detected on physical growth, which ruled out confounding effects of maternal nutrition, metabolism, etc. Taken together, these results suggest that the developmental trajectory of MALT and Control infants is different, marked by heightened levels of emotional reactivity, increased HPA activity and alterations in mother-infant interactions in MALT animals. These findings appear to be due to specific effects of postnatal maternal care, and not to biological/ behavioral traits inherited from the mother, or due to prenatal programming caused by prenatal stress, as the cross-fostering design controlled for these potential factors. However, we also detected a couple of interesting biological effects suggesting heritable transmission of some phenotypes. The prolonged HPA axis activation during the first 6 postnatal months of life is expected to have long-term consequences for brain, physiological, and behavioral development in MALT offspring.
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Affiliation(s)
- K M McCormack
- Department of Psychology, Spelman College, Atlanta, GA, USA; Emory National Primate Research Center, Emory University, Atlanta, GA, USA.
| | - B R Howell
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA; Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA; Department of Human Development and Family Science, Virginia Tech, Blacksburg, VA, USA
| | - M Higgins
- School of Nursing, Emory University, Atlanta, GA, USA
| | - S Bramlett
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA
| | - D Guzman
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - E L Morin
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - C Villongco
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Y Liu
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA
| | - J Meyer
- Department of Psychological & Brain Sciences, University of Massachusetts, Amherst, MA, USA
| | - M M Sanchez
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA
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Howell BR, Ahn M, Shi Y, Godfrey JR, Hu X, Zhu H, Styner M, Sanchez MM. Disentangling the effects of early caregiving experience and heritable factors on brain white matter development in rhesus monkeys. Neuroimage 2019; 197:625-642. [PMID: 30978495 DOI: 10.1016/j.neuroimage.2019.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 03/30/2019] [Accepted: 04/03/2019] [Indexed: 10/27/2022] Open
Abstract
Early social experiences, particularly maternal care, shape behavioral and physiological development in primates. Thus, it is not surprising that adverse caregiving, such as child maltreatment leads to a vast array of poor developmental outcomes, including increased risk for psychopathology across the lifespan. Studies of the underlying neurobiology of this risk have identified structural and functional alterations in cortico-limbic brain circuits that seem particularly sensitive to these early adverse experiences and are associated with anxiety and affective disorders. However, it is not understood how these neurobiological alterations unfold during development as it is very difficult to study these early phases in humans, where the effects of maltreatment experience cannot be disentangled from heritable traits. The current study examined the specific effects of experience ("nurture") versus heritable factors ("nature") on the development of brain white matter (WM) tracts with putative roles in socioemotional behavior in primates from birth through the juvenile period. For this we used a randomized crossfostering experimental design in a naturalistic rhesus monkey model of infant maltreatment, where infant monkeys were randomly assigned at birth to either a mother with a history of maltreating her infants, or a competent mother. Using a longitudinal diffusion tensor imaging (DTI) atlas-based tract-profile approach we identified widespread, but also specific, maturational changes on major brain tracts, as well as alterations in a measure of WM integrity (fractional anisotropy, FA) in the middle longitudinal fasciculus (MdLF) and the inferior longitudinal fasciculus (ILF), of maltreated animals, suggesting decreased structural integrity in these tracts due to early adverse experience. Exploratory voxelwise analyses confirmed the tract-based approach, finding additional effects of early adversity, biological mother, social dominance rank, and sex in other WM tracts. These results suggest tract-specific effects of postnatal maternal care experience versus heritable or biological factors on primate WM microstructural development. Further studies are needed to determine the specific behavioral outcomes and biological mechanisms associated with these alterations in WM integrity.
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Affiliation(s)
- Brittany R Howell
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA; Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Institute of Child Development, University of Minnesota, Minneapolis, MN, USA.
| | - Mihye Ahn
- Department of Mathematics and Statistics, University of Nevada, Reno, NV, USA; Department of Biostatistics and Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, USA
| | - Yundi Shi
- Department. of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Jodi R Godfrey
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Xiaoping Hu
- Biomedical Imaging Technology Center, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
| | - Hongtu Zhu
- Department of Biostatistics and Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, USA
| | - Martin Styner
- Department. of Psychiatry and Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Mar M Sanchez
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA, USA; Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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