STRESS AND ATTACHMENT
Tactile contact or the sense of touch, is the strongest determinant of attachment among primates; young individuals deprived of tactile contact may develop autistic-like behaviors. Early tactile deprivation reduces glucocorticoid (hormones produced by the adrenal gland which regulate protein, carbohydrate and fat metabolism) binding sites in the hippocampus (a part of the brain that is important for learning and memory) and frontal cortex (portion of the brain involved with reasoning, planning, abstract thought and other complex cognitive functions in addition to motor function). Thus, hypothalamic-pituitary-adrenal (HPA)-axis hormones mediate responses to tactile contact and subsequent attachment. Newborn rats are hyporesponsive to HPA activation. If removed from its mother, however, the young rat's HPA-axis becomes very reactive and may remain so throughout life. This hyperreactivity is tempered if some elements of maternal interaction are maintained (stroking, licking, feeding). Thus maternal behaviors buffer HPA-axis reactivity.