FUNCTIONAL MRI OF HUMAN MOTOR CORTICES DURING OVERT AND IMAGINED FINGER MOVEMENTS

A T-2-weighted echo-planar imaging technique at 4T was employed to pr oduce functional maps of the human motor cortices during overt and ima gined movements. Tasks required subjects either to perform or imagine a visually cued sequence of digit-to-thumb oppositions. The following significant functional changes were observed: 1) Contralateral primary motor cortex showed attenuated activity during the imagined tasks; 2) bilateral supplementary motor area and premotor cortices were active during both the visually instructed movements and the imagined finger movements; and 3) superior parietal cortex showed varying degrees of a ctivation in subjects performing the movement and imagined tasks. In p reliminary data, task-related activation of the primary motor cortex d uring imagined finger movements was observed in all subjects, suggesti ng that the motor cortex may indeed have ''premotor'' functions in add ition to its classically assigned function solely as a muscle controll er. (C) 1995 John Wiley & Sons, Inc.