Three-dimensional eye movement recordings during magnetic vestibular stimulation

Area of Science:

• Neuroscience
• Vestibular System Physiology

Background:

• Magnetic Resonance Imaging (MRI) scanners generate strong magnetic fields that can induce sensations of dizziness and vertigo in humans.
• These effects are known to originate from the stimulation of the vestibular labyrinth, often manifesting as nystagmus (involuntary eye movements).

Purpose of the Study:

• To investigate which specific semicircular canals within the vestibular system are activated by magnetic vestibular stimulation.
• To characterize the three-dimensional nystagmus patterns generated by exposure to a 7 Tesla (7T) MRI environment.

Main Methods:

• Utilized high-resolution video eye tracking to precisely measure the three-dimensional nystagmus in five healthy human subjects.
• Subjects were placed within a 7T MRI scanner to experience controlled magnetic vestibular stimulation.

Main Results:

• Observed nystagmus that consistently included both torsional (rotational) and horizontal components.
• Analysis of eye movement velocities indicated that the lateral and anterior (superior) semicircular canals were the sole canals activated by the magnetic fields.
• The activation levels for the lateral and anterior canals were found to be similar.

Conclusions:

• Magnetic vestibular stimulation in a 7T MRI predominantly activates the lateral and anterior semicircular canals.
• The findings provide insights into the mechanisms of vestibular stimulation by strong magnetic fields, relevant for MRI safety and understanding sensory perception.