Interpersonal neurobiology focuses on the relationship between early attachment experiences and the “wiring” of the brain. Understanding neurobiology has resulted in a deeper appreciation of how the earliest relationships shape child development and have an influence later in life. Brain development in infancy is experience dependent; the baby’s brain, specifically the limbic system, relies on sensitive and attuned care from attachment figures for healthy growth and functioning. Early relationship experiences play an essential role in shaping the architecture of the brain and building connections between parts of the brain. Chronic stress associated with lack of safe and secure attachment can impair the formation of brain circuits and alter levels of stress hormones (cortisol, dopamine, serotonin, epinephrine, norepinephrine), resulting in emotional and biological dysregulation, anxiety, and depression.
Brain development begins two weeks after conception and continues most rapidly during the first three years of life. Our brains are basically social in nature. Prenatal stress produces increased norepinephrine (arousal
and agitation) and decreased levels of dopamine and serotonin (depression, anxiety, emotional dysregulation). Brain circuits are being created rapidly in the the first year of life, and are significantly influenced by the quality of the infant–caregiver relationship and the level of stress. Babies are right-hemisphere dominant, responding primarily to preverbal and nonverbal emotional communication—facial expressions, mutual gaze, touch, tone of voice, and in-arms security and safety.
The infant’s right brain and the attachment figure’s right brain are in-synch and attuned during moments of loving and safe connection. This limbic resonance is the fundamental building block of secure attachment, and leads to the child’s ability to self-regulate and to the formation of the child’s core beliefs (i.e., internal working model). The sensitive caregiver calms, soothes and down-regulates the baby’s emotions and physical stress response, and later the child learns self-regulation. Early experiences of secure or insecure attachment are encoded into the implicit (preverbal and unconscious) memory systems in the limbic brain, and become mindsets and expectations that guide subsequent behavior (e.g., attachment figures are safe or unsafe, accepting or rejecting). Studies have found that infant attachment security predicts self-control six years later.
Neurons are brain cells that play a central role in processing and communicating information. Communication between neurons occurs via neurotransmitters that excite or inhibit electrical and chemical messages.
Relationship experiences of the infant and young child develop into neural networks that determine thoughts, moods, behaviors and attachment style: “what fires together, wires together.”
Children deprived of quality attachment relationships have abnormal brain development, as illustrated by the findings of the Bucharest Early Intervention Project. This research followed three groups of children: 1) institutionalized group—children living in an orphanage all their lives; 2) foster care group—children institutionalized at birth then placed in foster care at a mean age of 22 months; and 3) never institutionalized group—children living with their biological parents in the Bucharest, Romania area. The institutionalized children have stunted and delayed patterns of brain activity, cognitive development, and physical growth. Children placed in foster care before age 2 show patterns of brain activity similar to never institutionalized children, indicating the importance of placing children in families early to reduce the negative effects of deprivation and compromised attachment.
