Ontogeny of starvation-induced behavioral arousal in the rat.

Abstract

Spontaneous locomotor activity of neonatal and weanling rats was measured in stabilimeter activity cages scaled to the size of the animals under a wide range of temperature and food-deprivation conditions. Activity was low for the first 10 days of life and then increased sharply, reaching a peak nearly 10 times that of normal adult animals 16-20 days postpartum. Activity then declined rapidly to near-adult levels by 28 days of age. This dramatic change in the activity levels of the developing rat is correlated with major ontogenetic changes in the structure and functioning of the central nervous system. 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.In a classic series of papers, Hughlings-Jackson (collected in Taylor, 1931, 1932 proposed that the development of the central nervous system proceeds in a caudalcranial direction with later maturing higher systems acquiring control over early maturing more primitive systems. Numerous studies examining the morphological, electrophysiological, and biochemical maturation of the central nervous system support this general principle of development. Thus, the rate of myelin formation (Jacobson, 1963), increases in neurotransmitter levels and their metabolizing enzymes (Robinson, 1967(Robinson, ,1968, and many other indices of functional and morphological maturity appear first in the spinal cord, then in the brainstem, and finally in the diencephalon and telencephalon. In a like fashion, considerable evidence suggests that the later maturing centers act to modulate or control early developing structures. Simple motor reflexes that are present early in infancy, for example, disappear as telencephalic structures reach

Comparison of infant and adult rats in exploratory activity, diurnal patterns, and responses to novel and anxiety-provoking environments.

“…Infant rats are vigilantly kept in the protective maternal nest by their mothers until around P17-P18 (Barnett, 1958;Galef & Clark, 1972; Pereira & Morrell, 2007;Small, 1899), when they are allowed out into their larger environment. At this point, they have full motor and sensory capacity (Moorcroft, Lyttle, & Campbell, 1971). Experiences at this point readily produce longCorrespondence concerning this article should be addressed to Kiersten S. Smith, Center for Molecular and Behavioral Neuroscience, Rutgers University, 197 University Avenue, Newark, NJ 07102.…”

“…There is substantial information for adult rats, including diurnal locomotor activity and open-field activity measures (Joutsiniemi, Leinonen, & Laakso, 1991;Richter, 1922;Shirley, 1928), wheel running patterns (Bauer, 1990;Eikelboom & Mills, 1988;Peng, Jiang, & Hsu, 1980;Stewart, Rosenwasser, & Adler, 1985), rearing (Gregory, 1967;Hughes, Blampied, & Stewart, 1975;Kalinichev, Easterling, & Holtzman, 2002), and grooming (Borchelt, 1980;Jolles, Rompa-Barendregt, & Gispen, 1979;Sachs, 1988). Studies examining young rats focus mostly on adolescents (Barron, Hansen-Trench, & Kaiser, 1996;Campbell & Mabry, 1973;Hastings, Cooper, Bornschein, & Michaelson, 1977;Kalsbeek, de Bruin, Matthijssen, & Uylings, 1989;Livesey & Egger, 1970), although a few studies have been done in the infant rat.Simple measures of total activity demonstrate that infants are generally more active in the dark than in the light phase of the daily cycle (Bolles & Woods, 1964;Norton, Culver, & Mullenix, 1975), have considerable locomotor capacity (Moorcroft et al, 1971;Norton et al, 1975), are capable of rearing and grooming (Campbell & Mabry, 1973), and are capable of wheel running (Dalton-Jez & Eikelboom, 2005). Environmental novelty or familiarity significantly influences adult activity (Buelke-Sam, Sullivan, Kimmel, & Nelson, 1984;Galani, Duconseille, Bildstein, & Cassel, 2001), and some infant studies have a limited consideration of this (Buelke-Sam et al, 1984;Eilam & Golani, 1988;Golani et al, 2005;Pappas, Vickers, Buxton, & Pusztay, 1982).…”

Some aspects of the development of sex differences in DRL behavior

“…The rapid acquisition of DRL behavior by young rats of both sexes in light of the much poorer performance by adult males in earlier studies was surprising considering what is known of the ontogeny of activity (e.g., Moorcroft, Lytle, & Campbell, 1971) and passive avoidance behavior (Riccio, Rohrbaugh, & Hodges, 1968;Schulenburg, Riccio, & Stikes, 1971) in the rat. We suspected that the apparently better performance by younger males might reflect some procedural difference between the earlier study with adults (Beatty, 1973) and Experiment I.…”

A developmental analysis of the relationship between response strength and punishment

“…In the previous passive avoidance research, the suppression measure depended on the nonresponse of the subject. Since previous research had shown that there was an age difference in activity (Moorcroft, Lytle, & Campbell, 1971), the obtained age difference in suppression in the passive avoidance studies may have been influenced by this factor.…”