Table 1. Seasonal comparison of TH-ir fiber density in the auditory system.

Auditory Nucleus	Winter	Summer	P-value*
Dorsolateral division of the descending octaval nucleus + medial octavolateralis nucleus	↑	↓	0.029
Ventral secondary octaval nucleus	-	-	0.733
Octavolateralis efferent nucleus	↓	↑	0.0001
Torus semicircularis	-	-	0.297
Central posterior nucleus of the thalamus	↓	↑	0.03
Lateral division of nucleus preglomerulosus	↓	↑	0.0003
Anterior tuberal nucleus	-	-	0.201

Arrows indicate direction of significant differences between reproductive (summer) and non-reproductive (winter) females.

TH-ir, tyrosine hydroxylase immunoreactivity.

*P-values represent results from 2-tailed independent groups t-test.