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. 2004 Nov;11(6):738–747. doi: 10.1101/lm.75304

Figure 1.

Figure 1.

Visual-evoked potentials reveal an effect of monocular deprivation in fully mature mice. VEPs measured as a function of stimulus contrast in nondeprived animals show that responses of the left and right hemispheres are equivalent and mirror image (A). Following deprivation of 4 d, a difference develops between the left and right hemispheres (B). Inset graphs show the amplitude of evoked potentials as a function of contrast of the grating stimulus from a single adult animal. The amplitude (ordinate) increases with increasing contrast (abscissa) of the visual stimulus. In nondeprived animals, the amplitude from the contralateral visual input is about twofold larger than the amplitude from the ipsilateral input. Following deprivation, this difference sometimes declines in the left cortex but becomes greater in the right cortex. The large graphs show group-normalized contrast-response curves. The curves represent averages for 16 nondeprived mice and 19 right-eye deprived adults (ages P91-P415). (C) For the purpose of statistical comparison, amplitude data was transformed into contralateral bias indexes (CBI). In juveniles as well as adults, a difference between left and right hemispheres was observed following 4 d of monocular deprivation. There was no left/right difference in nondeprived (ND) mice. ANOVA (age group × hemisphere) yields a significant effect of hemispheres (P < 0.001) and a trend-level hemispheres × age interaction (P = 0.09). This trend-level interaction indicates that plasticity may weaken with age. All three deprived groups show a significant difference between left and right hemispheres (juvenile, P < 0.001; intermediate, P < 0.05; adult, P < 0.01, Bonferroni test corrected for four comparisons). n = 10 mice (juveniles), 14 (intermediate), 19 (adults). n = 16 mice for ND (four juveniles, four young, eight adults). CBIs for ND mice did not vary with age. (D) CBIs of individual hemispheres for all 19 right-eye-deprived adult animals. In almost all cases, the CBI of the right cortex was greater than the CBI of the left cortex, and this did not change with age.