Summary: Previously, using positron emission tomogra phy (PET), we showed that local cerebral metabolic rates for glucose (lCMRglc) in children undergo dynamic mat urational trends before reaching adult values. In order to develop an animal model that can be used to explore the biological significance of the different segments of the lCMRglc maturational curve, we measured lCMRglc in kit tens at various stages of postnatal development and in adult cats using quantitative [14C]2-deoxyglucose autora diography. In the kitten, very low lCMRg1c levels (0.14 to 0. 53 f.Lmol min -I g -I ) were seen during the first 15 days of life, with phylogenetically older brain regions being generally more metabolically mature than newer struc tures. After 15 days of age, many brain regions (particu larly telencephalic structures) underwent sharp increases of lCMRglc to reach, or exceed, adult rates by 60 days. This developmental period (15 to 60 days) corresponds to the time of rapid synaptic proliferation known to occur in the cat. At 90 and 120 days, a slight decline in lCMRglc Using positron emission tomography (PET), we have previously described the distribution and ab solute rates of local cerebral glucose utilization in the normal human brain from birth to adulthood (Chugani and Phelps, 1986;Chugani et al., 1987 Abbreviations used: BHB, f3-hydroxybutyrate ; 2DG, 2-deoxyglucose; PET, positron emission tomography .
35was observed, but this was followed by a second, larger peak occurring at about 180 days, when sexual matura tion occurs in the cat. Only after 180 days did ICMRglc decrease to reach final adult values (0.21 to 2.04 f.Lmol min -I g -I ) . In general, there was good correlation be tween the metabolic maturation of various neuroanatom ical regions and the emergence of behaviors mediated by the specific region. At least in the kitten visual cortex, which has been extensively studied with respect to de velopmental plasticity, the "critical period" corre sponded to that portion of the lCMRg1c maturational curve surrounding the 60-day metabolic peak. These nor mal maturational ICMRglc data will serve as baseline val ues with which to compare anatomical and metabolic plasticity changes induced by age-related lesions in the cat. Key Words: Cerebral glucose utilization-Brain de velopment-Positron emission tomography-Auto radiography-Plasticity-Cat.metabolic rates for glucose (lCMR g lc) in most brain areas undergo dynamic maturational changes over a rather protracted period. The typically low neonatal values of ICMR g lc rapidly increase from birth and begin to exceed adult values in the second and third postnatal year. By about 4 years, a plateau is reached that extends until about 9 years; following this, there is a gradual decline in ICMR g lc to reach adult values by the end of the second decade. The relative increase in ICMR g lc over adult values is most pronounced in neocortical regions, which at their peak have over a twofold higher ICMR g lc than corresponding adult values. Phylogenetically older structures (e.g.,...