Cerebellar Involvement in Visual On-Line Adaptation of Vertical Stroke Size: A PET Activation Study

Introduction: Behavioral data suggest that visual feedback can be effectively used for on-line adjustment of letter size during open-loop automated handwriting (Mai et Marquart Exp Brain Res 1999; 128: 224–228). Objective: Our intent was to pinpoint the involvement of the cerebellum in visual on-line adaptation of letter size. Methods: In eight male right-handed subjects (age: 25–39 years), we used H2 15O positron emission tomography (PET) to measure regional cerebral blood flow (rCBF) during a handwriting task and a control condition (holding the pen). The written trace was recorded using a graphics tablet. Vis…