To correct for misalignment, the anterior commissure and posterior commissure were aligned on the horizontal plane.  The interhemispheric fissure was also aligned to correct for brain tilt.  This alignment was accomplished using the acpcdetect program, a module of the Automatic Registration Toolkit (ART).  Version 2011-04-05 of the program was downloaded from https://www.nitrc.org/frs/?group_id=90.  An option was added to place the origin at the midpoint (-M) between the anterior and posterior commissures.