. 2011 Mar 23;105(6):2729–2739. doi: 10.1152/jn.00823.2010

Table 1.

Lesion-induced changes to juvenile song structure

	DLM_subsong (n = 7)	DLM_plastic (n = 7)	Area X_subsong (n = 12)	Area X_plastic (n = 7)	MMAN_subsong (n = 3)	LMAN (n = 8)
Syllable duration variability	0.85 ± 0.02	0.79 ± 0.06	0.86 ± 0.02^.	0.78 ± 0.08	0.85 ± 0.01	0.82 ± 0.06
	(0.65 ± 0.15)^†	(0.60 ± 0.11)^†	(0.84 ± 0.05)^NS	(0.73 ± 0.07)^NS	(0.87 ± 0.03)^NS	(0.66 ± 0.16)^*
Gap duration variability	0.87 ± 0.04	0.82 ± 0.04	0.87 ± 0.02	0.82 ± 0.06	0.88 ± 0.03	0.84 ± 0.05
	(0.72 ± 0.11)^†	(0.66 ± 0.13)^†	(0.85 ± 0.02)^NS	(0.80 ± 0.08)^NS	(0.88 ± 0.03)^NS	(0.72 ± 0.14)^*
Rhythmicity	0.08 ± 0.05	0.17 ± 0.07	0.15 ± 0.04	0.24 ± 0.05	0.18 ± 0.08	0.17 ± 0.07
	(0.32 ± 0.17)^*	(0.42 ± 0.20)^*	(0.14 ± 0.04)^NS	(0.25 ± 0.06)^NS	(0.14 + 0.04)^NS	(0.32 ± 0.14)^*
Average spectrogram cross-correlation	0.43 ± 0.18	0.41 ± 0.07	0.44 ± 0.14	0.41 ± 0.10	0.63 ± 0.03	0.33 ± 0.09
	(0.55 ± 0.16)^*	(0.52 ± 0.13)^*	(0.47 ± 0.16)^NS	(0.44 ± 0.10)^NS	(0.65 + 0.02)^NS	(0.40 ± 0.13)^*

Data are mean ± SE prelesion and postlesion (in parentheses) values for n birds. Four measures of song variability were used to analyze the effect of DLM (medial portion of dorsolateral thalamus) and Area X lesions on subsong and plastic song birds, of MMAN (medial magnocellular nucleus of anterior nidopallium) lesions on subsong birds, and of LMAN (lateral magnocellular nucleus of anterior nidopallium) inactivations on young plastic song birds. 1–2) Syllable and gap duration variability measures are entropy-based metrics of variability in syllable and gap duration distributions, where 0 and 1 represent maximal stereotypy and variability, respectively. 3) Song rhythmicity was computed as the peak of the power spectrum of song amplitude, where larger values correspond to increased repetitive song temporal structure. 4) The average spectrogram cross-correlation was computed from 250 pairwise cross-correlations performed on randomly chosen syllales from pre- and postlesion data sets. Values of 0 and 1 represent dissimilar and identical syllable acoustic structure, respectively (see [scap]methods[r]).

P < 0.05;

^†

†P < 0.01; NS, not significant. See text for details.