highly significantp < 0.001
A highly significant effect of age was found in the within-litter analysis [F(1.84, 14.75) = 1132.01, p < 0.001; η 2 = 0.99], as well as a significant age by neonatal condition interaction [F(1.84, 14.75) = 17.16, p < 0.001; η 2 = 0.68].