Experience-dependence of neural responses to social versus isolate conspecific songs in the forebrain of female Zebra Finches

Early exposure to conspecific song influences the ontogeny of behavioural discrimination between social and isolate songs of males in non-singing female Zebra Finches (Taeniopygia guttata). We explored the potential neural basis of this behavioural plasticity in song preference of female Zebra Finches, reared by both parents in a conspecific colony (controls) or by mothers only in sound-attenuation chambers (father-absent treatment). Comparing extracellular recordings of auditory neurons in the primary auditory forebrain area Field L showed that single units consistently responded with greater response strengths to male songs, over the synthetic stimuli of both frequency-matched pure tone assemblages and reversed conspecific songs, irrespective of females' ontogenetic treatment. Contrary to expectations, consistent response selectivity for social versus isolate Zebra Finch songs was detected from neurons only in father-absent females and not in control subjects. These results based on statistical analyses of data from single neurons were confirmed by a contingency analysis that used female subjects as independent datapoints. Our findings suggest that differences in the early social and/or auditory experience affect the neurophysiological responses to specific classes of male songs in auditory forebrain neurons of female Zebra Finches. Contrary to expectations, patterns of neuronal discrimination in the Field L complex do not parallel patterns of experience-dependent behavioural discrimination between social and isolate conspecific songs.