Brain metabolic differences as a function of hemisphere, writing hand preference, and gender

A total of 35 university-educated normal men (24 right handwriters and 11 left handwriters) and 36 age- and education-matched women (25 right handwriters and 11 left handwriters) underwent a proton magnetic resonance spectroscopy examination in seven 8 cm(3) voxels including the right and left frontal lobe tips, the right and left mid-temporal lobes, the right and left thalami, and the hypothalamus. Dependent measures were N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine/phosphocreatine (Cr) metabolite peak area ratios relative to total H2O. As expected, thalamic grey matter contained higher NAA ratios than telencephalic voxels (containing white and grey matter) (p<.001). The thalamic Cr/H2O ratio was higher on the right, but the opposite asymmetry was observed for the temporal lobe (p<.05). Women had a higher left frontal NAA/H2O ratio than men, but men had a higher hypothalamic NAA/H2O ratio than women. Right-handers had a higher temporal lobe NAA/H2O ratio than left-handers, particularly in the left hemisphere. In addition, several significant 2- and 3-way interactions between writing hand preference, gender, and hemisphere were observed, but only in the frontal lobe.