TSPO in situ hybridization in the adult AL after song playback experience. A) Representative images of AL (teardrop-shaped brain area in center of images) from males and females that heard either Silence or Novel song. B) The intensity of TSPO labeling showed a non-significant trend (p = 0.057) towards a decrease in birds that heard novel song. AL = auditory forebrain lobule, HP = hippocampus. Scale bar = 500 μm.