Reviews studies of mental rotation (MR), neural coding of the direction of movement, and neural activity during a mental transformation of the intended direction of movement. In a study of similarities between MR of the direction of movement and mental images, the authors (in press) compared the performances of human Ss in a visuomotor MR and a visual MR task. The processing rates (PRs) in both tasks were correlated, but neither rate correlated significantly with the PR in a visuomotor memory scanning task. These results suggest that visuomotor and visual Magnetic Resonance SpectroscopyMagnetic Resonance Spectroscopy (MRS)Used to roughly assess neuron health. Typically, we consider the ratios of N-acetyl aspartate, glutamine+glutamate, and choline over creatine. possess common processing constraints that could not be ascribed to general PR performances. (PsycINFO Database Record (c) 2016 APA, all rights reserved)