Neurobiology of infant attachment

Abstract

A strong attachment to the caregiver is critical for survival in altricial species, including humans. While some behavioral aspects of attachment have been characterized, its neurobiology has only recently received attention. Using a mammalian imprinting model, we are assessing the neural circuitry that enables infant rats to attach quickly to a caregiver, thus enhancing survival in the nest. Specifically, the hyper-functioning noradrenergic locus coeruleus (LC) enables pups to learn rapid, robust preference for the caregiver. Conversely, a hypo-functional amygdala appears to prevent the infant from learning aversions to the caregiver. Adult LC and amygdala functional emergence correlates with sensitive period termination. This study suggests the neonatal brain is not an immature version of the adult brain but is uniquely designed to optimize attachment to the caregiver. Although human attachment may not rely on identical circuitry, the work reviewed here suggests a new conceptual framework in which to explore human attachments, particularly attachments to abusive caregivers.

Brain corticotropin-releasing hormone (CRH) circuits in the developing rat: Effect of maternal deprivation

“…In contrast after this sensitive period (day 10) the odor-shock pairing results in a robust odor aversion. In the sensitive period, the learning of an odor preference does not involve amygdala activation, whereas in the post-sensitive period amygdala activation is required for the learning of the odor-shock aversion (Moriceau and Sullivan, 2005). Thus a hypo-functional amygdala during infancy appears to prevent the pup from learning aversions to the caregiver.…”

The Strategies of the Genes: Genomic Conflicts, Attachment Theory, and Development of the Social Brain

“…The neurological and endocrine bases for social motivation and affective bonding in infants (e. g., Bowlby 1969 p. 203-204;Moriceau and Sullivan 2005;Grossmann et al 2008) and children (e. g., Bartz and Hollander 2008) have been much less studied than those in mothers (e. g., Strathern et al 2009), though their relevance for understanding mother-child interactions should be no less consequential. Studies of plasma oxytocin levels in autism have yielded unusual results: two studies found lower plasma oxytocin in children with autism (Modahl et al 1998;Green et al 2001), but unexpectedly, oxytocin levels were positively associated with degree of social impairment (Modahl et al 1998); in the single study of adults, autistic individuals showed significantly higher levels of plasma oxytocin than did controls (Jansen et al 2006).…”

The neurobiology of social attachment: A comparative approach to behavioral, neuroanatomical, and neurochemical studies

“…Although various animal models have been developed to study social behaviors ubiquitous to mammalian species, including mating, maternal care, and aggression (Seay et al, 1962;Coe et al, 1978;Kendrick et al, 1992;Nelson et al, 2001;Weller et al, 2003;Levy et al, 2004;Moriceau et al, 2005;Hull et al, 2006;Hull et al, 2007;Nelson et al, 2007), the formation of strong bonds between mating pairs (pair bonding), and behaviors associated with these bonds, such as mate guarding (selective aggression) and paternal care, have been understudied, perhaps due to the lack of appropriate animal models. These behaviors are relatively uncommon in the animal kingdom, and in mammals are only displayed by the 3-5% of species that are monogamous (Kleiman, 1977).…”