Presenters: Natalia Jacobsen, Family, Home, and Social Sciences, Psychology
Authors: Elizabeth K. Wood, Natalia Gabrielle, Miranda J. Johnson, Jacob Hunter, Stephen J. Suomi, J. Dee Higley
Faculty Advisor: J. Dee Higley, Family, Home, and Social Sciences, Psychology, Neuroscience
Institution: Brigham Young University
A variety of studies show that maternal presence is critical for infant brain development, providing the necessary input for normative synaptic connection, neuronal survival, and healthy brain development, including the monoamine systems (i.e., serotonin, dopamine, and norepinephrine). To assess the effect of maternal input on the development of the monoamines 434 rhesus monkey infants (n=233 males and 201 females) were reared in one of two conditions: as controls reared by their mother (MR; n=269) or without mothers or other adults in same-aged, peer-only groups (PR; n=165). When subjects were six-months-old, they were genotyped for the serotonin transporter (5-HTT) polymorphism and underwent a series of 4, four-day separations from their mothers or in the case of the PR infants, from their peers, followed by 4, three-day reunions. Six cerebrospinal fluid (CSF) samples were obtained: baseline-prior to separations, during each of the 4 separations, and recovery-at the end of the separations, and assayed for monoamine metabolite concentrations. Replicating for the first time earlier landmark findings, PR subjects with the s allele exhibited lower baseline serotonin metabolite concentrations (5-HIAA), when compared to PR subjects with the L allele, and lower than the MR subjects that were undifferentiated by genotype. PR subjects also exhibited lower CSF 5-HIAA concentrations during baseline, but higher social separation-induced 5-HIAA concentrations, when compared to MR subjects. Results also showed that PR subjects exhibited higher dopamine metabolites (HVA) and lower norepinephrine metabolites (MHPG) than MR subjects. These findings indicate that there are long-term deficits in the stress-response of monoamine metabolite concentrations following early maternal absence. The results of this study confirm and extend earlier findings showing that early life parental absence has detrimental consequences for the development of the monoamine systems, and that these consequences are modulated by the 5-HTT genotype.