Noradrenergic control of auditory information processing in female canaries.

An ethological procedure, based on the study of the sexual responsiveness of female canaries (Serinus canaria) to song playbacks was used to investigate the function of central noradrenergic inputs in the processing of auditory information. The effects of a noradrenergic denervation on sexual responses was analyzed in females exposed to playbacks of biological relevant auditory stimuli, i.e. sexually stimulating songs, presented alone or masked by auditory distractors. A decrease in behavioral responsiveness was observed as a function of the amount of masking distractors indicating that female canaries have the perceptual ability to discriminate and selectively attend to biologically relevant songs. After the systemic administration of DSP-4, a specific noradrenergic neurotoxin, females exhibited an overall decrease in sexual responsiveness to songs masked or not by distractors. No effect of DSP-4 were detected on the motor activity nor on reproductive behaviors. These results indicate that central noradrenergic inputs modulate the sexual behavior of female canaries by affecting the auditory processing of relevant information contained in sexually stimulating songs.