Reciprocal connections between primary and secondary auditory pathways in the telencephalon of the budgerigar (Melopsittacus undulatus)

Among avian species that learn their vocalizations, budgerigars have been thought to be unusual in receiving auditory input to the vocal control circuitry of the telencephalon via an auditory component of nucleus basalis (NB), rather than via Field L2, the end station of the classical thalamofugal pathway. In the present study, however, the application of neural tracing techniques showed the two auditory pathways to be reciprocally connected within the telencephalon. The implication is, therefore, that auditory information essential for vocal learning and vocal production in the budgerigar is derived from the primary as well as the secondary auditory pathway.