Anesthetized values are taken from Achiro and Bottjer (2013); sleeping values are taken from current study. Each measure in the table was significantly different between CORE and SHELL in anesthetized birds whereas none of the comparisons varied between CORE and SHELL in sleeping birds. The mean age of birds at which recordings were made by Achiro and Bottjer (2013) was 45.5 dph (range 43–47); the mean age of birds from recordings in the current study was 48.5 dph (range 43–53).

↵a percentage of neurons that responded to playback of at least one song.

↵b percentage of neurons that were suppressed by song playback (cells that showed suppression only are included for both studies).

↵c percentage of neurons that gave a significant response only to TUT and not to any other stimulus [out of five songs by Achiro and Bottjer (2013), out of four songs for the current study].

↵d Selectivity scores for JuvCon versus TUT, OWN refer to average difference scores between standardized response strengths (see Materials and Methods). Scores from present study are for suppressed responses among JuvCon-selective cells, while scores by Achiro and Bottjer (2013) are for cells for TUT-selective and OWN-selective cells, respectively (Achiro and Bottjer scores include excited responses for CORE and excited and suppressed responses for SHELL); we chose to present scores for JuvCon-responsive cells from this study since so few neurons responded to TUT (Table 1).