Plasticity for Affective Neurocircuitry: How the Environment Affects Gene Expression

ABSTRACT— We ( Fox et al., 2005 ) recently described a gene-by-environment interaction involving child temperament and maternal social support, finding heightened behavioral inhibition in children homozygous or heterozygous for the serotonin transporter (5HTTLPR) gene short allele whose mothers reported low social support. Here, we propose a model, Plasticity for Affective Neurocircuitry, that describes the manner in which genetic disposition and environmental circumstances may interact. Children with a persistently fearful temperament (and the 5HTTLPR short allele) are more likely to experience caregiving environments in which threat is highlighted. This in turn will exacerbate an attention bias that alters critical affective neurocircuitry to threat and enhances and maintains anxious behavior in the child.