Ontogeny of starvation-induced behavioral arousal in the rat.

Abstract

Measured spontaneous locomotor activity of 276 and 4 male Sprague-Dawley neonatal and weanling rats in stabilimeter activity cages scaled to the size of the Ss under a wide range of temperature and food-deprivation conditions. Activity was low for the 1st 10 days of life and then increased sharply, reaching a peak nearly 10 times that of normal adult animals 15-20 days postpartum. Activity then declined rapidly to near-adult levels by 28 days of age. This change in activity levels is correlated with major ontogenetic changes in the structure and functioning of the CNS. It is suggested that these changes may reflect a caudal-rostral sequence of development, in which brainstem excitatory centers and their afferent inputs mature earlier than do the more phylogenetically advanced telencephalic inhibitory centers. (32 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)