The precuneus in motor imagery: a magnetoencephalographic study

Magnetoencephalography was applied to subjects who imagined themselves hurd ling in self-centered space. In three of six subjects all 300 trials in the motor imagery condition revealed the precuneus dipole. When we divided the 300 trials into four overlapping blocks (one block = 150 trials), all six subjects showed precuneus activity. The latency of the precuneus dipole was about 220 ms. We suggest that the precuneus activity during motor imagery involves retrieval of spatial information and/or setting up spatial attribu tes. Only in one subject but twice, the current dipole located in the suppl ementary motor area was observed 60 ms after activation of the precuneus, w hich suggests that the signal from the precuneus for motor imagery is trans ferred to the supplementary motor area. NeuroReport 11:1345-1349 (C) 2000 L ippincott Williams & Wilkins.