CEREBELLAR VOLUME ASYMMETRIES ARE RELATED TO HANDEDNESS - A QUANTITATIVE MRI STUDY

Four cerebellar subregions were delineated (left, right; anterior, pos terior), and their volumes measured on contiguous 3.1 mm coronal MR im ages in 15 dextral and 8 nondextral healthy control subjects. (1) Left and right cerebellar hemisphere volume asymmetries interacted with an terior-posterior level (anterior: right>left; posterior: left>right), following a pattern commonly found in the neocortex; (2) A significant handedness effect was found (P<0.01) on a composite index of cerebell ar asymmetry, such that dextrals showed more asymmetry than nondextral s. These data suggest that the same pattern of asymmetries observed at the neocortical level is also present in the metencephalon. These asy mmetries, possibly resulting from multiple developmental growth gradie nts acting on the metencephalon early in gestation, are associated wit h handedness differences in adulthood.