Biochemical markers of intelligence: a proton MR spectroscopy study of normal human brain

Proton magnetic resonance spectroscopy (H-1-MRS) offers a unique non-invasi ve approach to measurement of N-acetylaspartate (NAA) and choline (Cho), pu tative markers of neuronal and glial integrity. Previous studies revealed t hat these neurochemicals predict cognitive impairment in diseased subjects, although little is known about their relationship to cognitive functioning in healthy people. We measured the concentrations of NAA and Cho in the le ft occipitoparietal white matter of 26 healthy adults and compared them wit h intellectual performance assessed by the Wechsler Adult Intelligence Scal e-3. We found that NAA (b = 0.6, p < 0.01) and Cho (b = -0.42, p < 0.01) we re independently associated with the Full-Scale Intelligence Quotient. Toge ther, these metabolites accounted for a large proportion of the variance in intelligence (r(2) = 0.45). Possible mechanisms underlying these correlati ons, such as mitochondrial function and myelin turnover, are discussed. H-1 -MRS is a sensitive new tool to assess the neuronal underpinnings of cognit ive function non-invasively.