Rodent Brain Growth Stages: An Analytical Review

Abstract

Study of data in the literature on rat and mouse brain growth from birth to weaning reveals a stagewise growth in average brain weight. Rapid growth occurs in the intervals between days 0–6, 8–12, and 17–23 after birth. Slow growth periods then lie in the intervals 6–8, 12–17, and after 23 days. The first slow growth period is signalled by events occurring at its end: substantial acceleration of synthesis of RNA, DNA, protein, and myelin. The second slow growth period is characterized by at least a 3-day interval during which there is very little increase in average brain weight compared with what occurs just before and just after that period; the correlation among 12 studies is highly significant. Implications are discussed for cross-species’ extrapolation of findings about brain development.

Passive avoidance during brain-growth spurts and plateaus

“…A recent study by Hahn, Walters, and DeLuca (Note 2) found that 12-day-old animals are in a plateau rather than a spurt, as previously reported by Gottlieb et al (1977). We tested mice in a passive avoidance situation at 11, 15, and 19 days of age, since 11-and 19-day-old animals are in established spurts and 15-day-old animals are in an established plateau.…”

“…Epstein (1979) has shown a stagewise growth in average brain weight, and he correlates these braingrowth stages with mind-growth stages, or Piaget's stages of intellectual development. He suggests that the normal course of human brain development is not a linear process but, rather, is characterized by specific stages of rapid and slow growth, or spurts and plateaus, respectively.A study by Gottlieb, Keydar, and Epstein (1977) on mouse and rat brain growth from birth to weaning shows rapid growth (spurts) at 0-6, 8-12 or 13, and 17-23 days, and slow growth (plateaus) at 6-8,12-17, and after 23 days of age. Epstein's (1979) work predicts a decrement in learning ability at a plateau and increased learning in a spurt.…”

“…A study by Gottlieb, Keydar, and Epstein (1977) on mouse and rat brain growth from birth to weaning shows rapid growth (spurts) at 0-6, 8-12 or 13, and 17-23 days, and slow growth (plateaus) at 6-8,12-17, and after 23 days of age. Epstein's (1979) work predicts a decrement in learning ability at a plateau and increased learning in a spurt.…”

Effective treatments of prolonged status epilepticus in developing rats

“…In this study, we evaluated the effectiveness of DZP and PTB in stopping 1-hour long SE induced either by kainic acid (KA) or lithium-pilocarpine (Li-Pilo) in developing male rats at postnatal day (P)9, 15 and 21 which may correspond to a newborn (14)(15)(16)(17), toddler (18) and young child respectively (19,20). KA is a glutamate receptor agonist and pilocarpine is a muscarinic acetylcholine receptor agonist; both agents induce a partial onset SE with secondary generalization.…”

Effects of lead and/or zinc exposure during the second stage of rapid postnatal brain growth on delta-aminolevulinate dehydratase and negative geotaxis of suckling rats

“…During the postnatal period rodents present three stages of rapid brain growth (4) in which they are especially prone to neurotoxicants (5,6). However, there are few studies in the literature concerning the effects of lead on specific stages of postnatal brain development (6).…”