Fig. 1.

A, LMAN neurons become song and order selective between 30 d and adulthood. At 30 d neurons have equal response strengths (RS) to tutor song (TUT), conspecific song (CON), and tutor reverse (REV), whereas in adulthood, BOS elicits greater RS than CON or BOS reverse (REV) (data fromDoupe, 1997). B, Time course of zebra finch song learning. Juveniles learn their song in two overlapping phases; the sensory phase ends at ∼60 d, and the sensorimotor phase begins at ∼30 d and continues to adulthood (90+ d). C, The anatomy of the song system is illustrated, with the nuclei of the anterior forebrain in black and those of the motor pathway in gray.