The mesocortical dopamine system plays a critical role in the development and functioning of frontal systems involved in attention and emotion regulation (Berridge and Robinson, 1998; Diamond, 1998). Adverse early caregiving disturbs the development of the dopamine system in the nucleus accumbens (Hall et al., 1998), and the effects of stressful stimulation on this system are enhanced in the presence of elevated GCs (Piazza and LeMoal, 1996). Though, there is a highly coupled dopaminergic circuit, the mesocorticolimbic system, of which the nucleus accumbens is only one part (Pierce and Kalivas, 1997). The prefrontal cortex essentially puts the brakes on dopamine secretion in the nucleus accumbens. However, although acute stressors stimulate neurons in the ventral tegmental area to secrete dopamine in both the nucleus accumbens and the prefrontal cortex, repeated stressors facilitate dopamine secretion in the nucleus accumbens, but inhibit it in the prefrontal cortex (Sorg and Kalivas, 1991; Sorg and Kalivas, 1993). It is quite possible that the stimulatory effect of the GCs on dopamine secretion in the nucleus accumbens is an indirect consequence of their actions on amygdalar function and the strong input from the extended amygdala to the nucleus accumbens (Swanson, 2000)
