Diagram of key components of the song system involved in song production, acquisition and maintenance. Black arrows represent the motor pathway and grey arrows represent the anterior forebrain pathway. Abbreviations: HVC, (proper name); LMAN, lateral magnocellular nucleus of the anterior nidopallium; RA, robust nucleus of the arcopallium; Area X (proper name); DLM, medial portion of the dorsolateral nucleus of the thalamus; nXIIts, tracheosyringeal part of the nucleus nervi hypoglossi. Based on Nottebohm et al., 1976; Bottjer et al., 1989.