There are also new areas of research, some represented in this collection, that are only just beginning to draw attention. Exciting work is underway on the neural underpinnings of adolescent psychopathology, social cognition, and stress responsivity, and we can look forward to a dramatic increase in our understanding of these phenomena over the next decade. Studies of genetic influences on brain development and on brain-behavior relations in adolescence are still in their infancy, as is research on individual differences in brain development that may have genetic underpinnings. And research on neurotransmission, which has heretofore focused mainly on the role of dopamine, is beginning to expand into other substances that may also have special significance in adolescence. For example, puberty-related increases in gonadal hormones have been linked to a proliferation of receptors for oxytocin within the limbic system, including such structures as the amygdala and nucleus accumbens (Spear, 2009). Oxytocin neurotransmission has been implicated in a variety of social behaviors, including facilitation of social bonding and recognition and memory for positive social stimuli (Insel & Fernald, 2004). Whether oxytocin-related changes undergird
