ABSTRACT
The ability to be continuously informed about external changes in the environment as well as about the current status of internal bodily states is a fundamental function of the brain. In early development this adaptive capacity is essential to the survival of the infant, and its emergence is a product of the incipient interactions between a developing brain and its social environment. The maturation of an evaluative system in the frontolimbic cortex is experience-dependent, and is specifically shaped by face-to-face synchronized interactions in which the caregiver psychobiologically attunes to the child’s internal state in order to form a system of mutually regulated arousal. Once this attachment bond is formed, the mother’s facially expressed emotional communications can be accessed in order to provide the infant with salient maternal appraisals of interactions and events that regulate his affect, cognition, and behavior. These “social referencing” attachment experiences are imprinted into and directly influence the organization of the orbital cortex, a prefrontal area that undergoes a critical period of growth from the last quarter of the first until the last quarter of the second year. This region hierarchically dominates the limbic system and directly connects into the autonomic nervous system, and it is expanded in the early developing right hemisphere that is dominant for the processing of socioemotional information and for the regulation of body state. Due to the organization of its dense connections with sites in both the cortex and subcortex, this system plays an essential psychobiological role – at the orbitofrontal level cortically processed exteroceptive information concerning the external environment (such as visual and prosodic information emanating from an emotional face) is integrated with subcortically processed interoceptive information regarding the internal visceral environment (such as concurrent changes in bodily states). This cortex, acting in an “evaluative” capacity, thus functions to refine emotions in keeping with current sensory input, and allows for the adaptive switching of internal bodily states in response to changes in the external environment that are appraised to be personally meaningful.
