Question

Vestibular signals combine with visual signals in certain areas of cortex and assist in motion perception. What types of cues does the visual system provide for self motion through space? What types of vestibular signals would be consistent with rotational versus translational motion?

Answer 1

In many regions of the brain, vestibular signals combined with visual signals in certain areas of cortex as well as with motor information to give rise to motion perception, body awareness and behavioral control. Visual cues provide a rich source of information about self-motion. Optic flow and vestibular signals are likely the two most sensitive cues for judging self-motion. Optic flow contributes to self-motion perception and  can elicit powerful illusions of self-motion. The vestibular system provides a powerful independent source of information about head motion in space. Specifically, vestibular sensors provide information about linear acceleration and the angular rotation of the head in space and thus provide important inputs to self-motion estimation.

A set of three inner ear vestibular receptors (horizontal, anterior, posterior) that transduce head rotational accelerations into head rotational velocity signals that are then transferred to the brain. There are three semicircular canals in each ear, with the major planes of each canal being orthogonal to each other. The vestibular receptors detect rotational motion (head turns), linear motion (translations) and tilts of the head relative to gravity and transduce these motions into neural signals that can be sent to the brain. But the combined rotational and translational head movements incurred during our stride. The vestibular system regulates compensatory eye, neck, spinal, and limb movements in order to maintain gaze.