Fig. 1.

Digital images of coronal sections, at thalamic level, of glutamic acid decarboxylase (GAD) (a, b, c) and enkephalin (ENK) (e, f, g) immunoreactivity (IR) in young, adult, and aged rats. Black arrows indicate intergeniculate leaflet (IGL), stained area between dorsal geniculate (dLGN) and ventral geniculate (vLGN) lateral nuclei. Scale bar, 100 μm. GAD-IR optical density (OD) measurements in arbitrary units (A.U.) of young (n = 5), adult (n = 5), and aged (n = 5) animals (d). One-way ANOVA did not reveal a significant effect of age on changes in GAD-IR OD [F(2,12) = 0.6420; p = 0.5434] between age groups. ENK-IR OD measurements in A.U. of young (n = 5), adult (n = 5), and aged (n = 5) animals (h). One-way ANOVA did not reveal a significant effect of age on changes in ENK-IR OD [F(2,12) = 1.177; p = 0.3414] between age groups