Figure 3. Perceived body rotation with GVS.

A, perceived rotation about the earth-vertical axis (Rˇ) produced by vestibular stimulation for the 5 head positions for 1 subject. Positive head pitch is bent forward (inset figures). With no stimulus (0), the subject realigned herself to within 4 deg of initial orientation. With cathode-left, anode-right stimulation (+R) she perceived rotation to the left but, with the head pitched back, the perceived rotation was to the right. Reversing stimulus polarity (+L) reversed these perceptions. B, group mean perceived rotation (±2 s.e.m.) is shown for stimuli of 0 mA (open squares), ±0.5 mA (semi-filled squares) and ±1.0 mA (filled squares). Responses are normalized to show perceived rotation towards the cathode (−i) as positive values.