Rat pup social motivation: A critical component of early psychological development

Abstract

Examining the role of the offspring in early social dynamics is especially difficult. Human developmental psychology has found infant behavior to be a vital part of the early environmental setting. In the rodent model, the different ways that a rodent neonate or pup can influence social dynamics are not well known. Typically, litters of neonates or pups offer complex social interactions dominated by behavior seemingly initiated and maintained by the primary caregiver (e.g., the dam). Despite this strong role for the caregiver, the young most likely influence the litter dynamics in many powerful ways including communication signals, discrimination abilities and early approach behavior. Nelson and Panksepp (1996) developed a preference task to examine early rodent pup social motivation. We have used the same task to examine how variations in maternal care or different environmental perturbations could alter the rat pup preferences for social-related stimuli. Rat pups receiving low levels of maternal licking and grooming were impaired in maternal odor cue learning and emitted lower levels of 22 kHz ultrasounds compared to pups from the high licking and grooming cohort. Prenatal stress or early exposure to a toxicant (polychlorinated biphenyl) altered early social preferences in the rat pup in different ways indicating that diverse strategies are expressed and specific to the type of perturbation exposure. A greater focus on the offspring motivation following early 'stressors' will allow for more complete understanding of the dynamics in behavior during early social development. KeywordsAttachment emotion; epigenetics; stress; toxicology Early social development involves dynamic interactionsThe idea that there is a continuous interaction between individuals during early development is not new (Bishop and Merrill, 1951;Sander, 1962;Wolff, 1963). Bowlby emphasized this fact throughout his writings (1973 (1982) and a significant amount of child developmental work has focused on different aspects of this dynamic social environment (Courage and Howe, 2002;Pelaez et al., 2008;Repacholi, 2009). This has included work on joint attention (Grossberg and Vladusich, 2010), interactive speech and learning (Gogate et al., 2000) and the gradual development of theory of mind (Wellman and Brandone, 2009). These different Address Correspondence to: Howard Casey Cromwell, Department of Psychology, Psychology Building, Bowling Green State University, Bowling Green Ohio 43403, hcc@bgsu.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Bowlby's work originated out of studies on animal ...

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