Lesions in the budgerigar vocal control nucleus NLc affect production, but not memory, of English words and natural vocalizations

This study investigates the role of the psittacid (parrot) central nucleus of the lateral neostriatum (NLc) in the production of learned English and natural vocalizations. Anatomic data have led researchers to define NLc alternately as the parrot homologue (Paton et al. [1981] J Neurosci. 11:1279–1288) or analogue (Striedter [1994] J Comp Neurol. 343:35–56) of the songbird high vocal center. Although numerous functional and electrophysiological studies have identified the role of various songbird vocal control nuclei, few similar functional studies have been performed in parrots, particularly with respect to NLc. In this study, both novel behavioral techniques and precise neurochemical lesions have been used to investigate the role of NLc in the production of learned vocalizations. The results suggest that NLc is involved in the production of, but not memory for, learned English and natural vocalizations. Specifically, NLc lesions disrupted the amplitude of amplitude-modulated vocalizations, but did not affect the frequency of the dominant or carrier signal of these vocalizations. These data provide some of the first evidence for the functional role of a parrot vocal control nucleus. J. Comp. Neurol. 421:437–460, 2000. © 2000 Wiley-Liss, Inc.