Continuous theta-burst stimulation of the right superior temporal gyrus impairs self-motion perception

Exp Brain Res. 2013 Oct;230(3):359-70. doi: 10.1007/s00221-013-3660-8. Epub 2013 Aug 8.

Abstract

Sensory input from the semicircular canals (SCC) and otolith organs is centrally combined with signals from other sensory modalities to continuously update the internal estimate of self-motion. Constant velocity vertical on-axis rotation leads to decay of the nystagmus response from the horizontal SCC and of perceived angular velocity (PAV), and when the rotation stops, a similar oppositely directed post-rotatory response occurs. Case reports and electrical stimulation studies suggest an involvement of the temporo-peri-Sylvian vestibular cortex in generating the PAV. Here, we transiently inhibited the right superior temporal gyrus (STG) by use of continuous theta-burst stimulation (cTBS) and predicted an accelerated decay of PAV compared to controls (n = 5 control session first, n = 1 cTBS session first). Constant velocity (100°/s) vertical on-axis rotations were applied over 75 s before (1 block) and after (3 blocks) cTBS over the right STG in six subjects. Breaks between the rotations (75 s) were initiated by abrupt stops. By use of a rotating potentiometer, subjects indicated the PAV during and after the chair rotations. Simultaneously eye positions were recorded using a scleral search coil. One subject was excluded for per-rotary analysis. Early after cTBS, the post-rotary PAV decay time constant (DTC) was significantly (9.4 ± 5.7 vs. 13.6 ± 5.9 s; p = 0.049) reduced (no directionality to this effect observed). Overall, post-rotary PAV showed a trend toward shortened DTC compared to the control trials (p = 0.086) in the first 25 min after cTBS, while per-rotary PAV was not significantly changed. Per-rotary and post-rotary aVOR DTC were not significantly changed after cTBS (p > 0.05). These findings support the hypothesis that the right STG is involved in mediating self-motion perception and can be modulated by cTBS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acceleration
  • Adult
  • Aged
  • Data Interpretation, Statistical
  • Eye Movements / physiology*
  • Female
  • Humans
  • Linear Models
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Motion Perception / physiology*
  • Motor Cortex / physiology
  • Muscle, Skeletal / physiology
  • Otolithic Membrane / physiology
  • Physical Stimulation
  • Pilot Projects
  • Reflex, Vestibulo-Ocular / physiology*
  • Rotation
  • Surveys and Questionnaires
  • Temporal Lobe / physiology*
  • Transcranial Magnetic Stimulation*