ELECTROPHYSIOLOGICAL EVIDENCE FOR DIRECTION-SPECIFIC ROTARY EVOKED-POTENTIALS IN HUMAN-SUBJECTS - A TOPOGRAPHICAL STUDY

The spatio-temporal characteristics of rotary evoked potentials are un known up to now. Transient motions with sinusoidal velocity profile (6 0 degrees, 47.12 degrees/s, 74.02 degrees/s(2), duration 2 s) were alt ernately applied (rightward/leftward) to 12 healthy subjects. Fixation of a target-cross moving with them suppressed the vestibule-ocular re flex. Quasi-DC-scalp potentials were recorded from a total of 21 equid istant (3 cm) locations (single sweep: 5 s, 0.016-100 Hz). Brain activ ity evoked by rotary stimulation is dominated by a late, long-lasting component within a mean peak latency of about 1800 ms after motion ons et. Topographic distribution over both hemispheres specifically depend s upon the direction of rotation and is mirror-symmetric with respect to the sagittal midline. The gradient of the potential field obtained shows its maximum along a lateral orientation corresponding to the tem poro-parietal orientation of vestibular cortical projection areas. (C) 1997 Elsevier Science Ireland Ltd.