Frequency of dopamine concentration transients during brief conspecific episodes: effects of presentation set and conspecific rat. A, Habituation of transients during the second presentation set, by brain region; *p < 0.0001. B, Frequency of transients in the presence of different conspecific rats, by brain region; *p < 0.05, greater than CP nonreceptive female; **p < 0.05, greater than NA male; #p < 0.05, greater than NA male, greater than CP nonreceptive female;##p < 0.05, greater than CP male.