Age-related glutamate and glutamine concentration changes in normal human brain: 1H MR spectroscopy study at 4 T.

Proton magnetic resonance spectroscopy was performed at 4 T to determine effects of age, region and gender on glutamate and glutamine in the normal human brain. Furthermore, glutamate and glutamine alterations with age were tested for correlations with other cerebral metabolites. Two 8 cm3 volumes were selected in corona radiata and mesial motor cortex in normal subjects (N = 24) between 24 and 68 years old. Older subjects had lower glutamate concentration in the motor cortex compared to younger subjects (p < 0.001). In corona radiata, older subjects demonstrated a trend in higher glutamine compared to younger subjects (p = 0.05). Glutamate in the motor cortex was positively correlated with glutamine, N-acetyl aspartate and creatine. Reduced glutamate and N-acetyl aspartate in the motor cortex is consistent with neuronal loss/shrinkage with age. In conclusion, different patterns in association with normal aging in these brain regions were detected in this study.