Receiving non-nurturing maternal care also has implications for maternal behavior. Female offspring of low-LG dams exhibit low LG toward their own offspring, while female offspring of high-LG dams exhibit high levels of LG toward their offspring. The medial preoptic area (MPOA) is a brain region instrumental in maternal behavior (Fleming et al., 1983; Fleming and Walsh, 1994; Numan, 2012; Pedersen et al., 1994). Females subjected to low LG in infancy demonstrate decreased ERα expression within the MPOA from infancy through adulthood (Champagne et al., 2006; Peña et al., 2013). Decreased gene expression corresponded with increased levels of methylation and reduced transcription factor binding at the exon 1b promoter region of ERα (Champagne et al., 2006). Cross-fostering experiments have shown that ERα expression is under the control of infant caregiver experience, as pups demonstrate ERα expression consistent with that of the dam that raised them rather than their biological mother (Champagne et al., 2006). Because ERα is a ligand-activated transcription factor, altering ERα expression can have implications for the transcription of other genes containing estrogen response elements (Marino et al., 2006).
