Maturational decrease of glutamate in the human cerebral cortex from childhood to young adulthood: a 1 H-MR spectroscopy study.

BackgroundThe aim of the present study was to investigate maturational changes in glutamate (Glu) in the human cerebral cortex from childhood to young adulthood using 3.0-Tesla proton magnetic resonance spectroscopy (1 H-MRS), which is capable of quantifying Glu in vivo.MethodsNormal volunteers comprising 11 children (aged 4-13 years) and 11 young adults (aged 18-33 years) participated in the study. Single-voxel point-resolved spectroscopy (PRESS, repetition time/echo time=2,000/80 ms) was performed on the frontal and occipital cortices, and the Glu-to-creatine ratio (Glu/Cr) and N-acetylaspartate-to-creatine ratio (NAA/Cr) were determined.ResultsIn both the frontal and occipital cortices, Glu/Cr was significantly lower during young adulthood relative to that during childhood. NAA/Cr did not differ significantly between the two age groups.ConclusionThis study has provided objective evidence that cerebral cortical Glu/Cr decreases between childhood and young adulthood. The observed decrease in Glu/Cr may reflect the simultaneous occurrence of maturational changes, such as changes in cortical microstructure and the intercellular compartmentation of Glu metabolism.