Glossary

Vestibular terms drawn from the atlas. 0 bookmarked.

22 terms

Afferent neurons☆ Bookmark

Sensory neurons transmitting signals from hair cells to the brain, classified into regular (tonic) and irregular (phasic) types by firing pattern and sensitivity.

Also: afferents, primary afferents

See also: Hair cells, Irregular afferents

Angular acceleration☆ Bookmark

A change in rotational velocity, sensed by the semicircular canals of the vestibular system.

See also: Semicircular canals

Burst-tonic (BT) neurons☆ Bookmark

Central neurons encoding both eye velocity and position, with a phasic burst followed by a sustained tonic discharge.

Also: BT neurons

See also: Neural integrator

Caloric test☆ Bookmark

A vestibular diagnostic that stimulates the horizontal canal with warm or cold irrigation of the external auditory canal, inducing nystagmus.

See also: Semicircular canals

Climbing fibers☆ Bookmark

Afferents from the inferior olive that synapse with Purkinje cells, carrying error signals such as retinal slip for motor learning in the cerebellum.

See also: Purkinje cells, Retinal slip, Inferior olive

Cosine tuning curve☆ Bookmark

The directional response profile of hair cells and afferent neurons, with maximal response when deflection aligns with the cell's polarity axis.

See also: Hair cells

Dark cells☆ Bookmark

Specialized cells in the vestibular labyrinth that maintain high potassium levels in endolymph, crucial for mechanoelectric transduction.

See also: Endolymph

Endolymph☆ Bookmark

Potassium-rich fluid within the membranous labyrinth that deflects the cupula or otolithic membrane during head motion.

See also: Dark cells

Hair cells☆ Bookmark

Sensory receptors of the vestibular system in the ampullae and maculae, bearing stereocilia and a kinocilium that detect fluid motion.

Also: type I hair cells, type II hair cells

See also: Cosine tuning curve, Afferent neurons

Head impulse test (HIT)☆ Bookmark

A bedside test of VOR function that detects semicircular canal deficits by observing corrective saccades during rapid head turns.

Also: HIT, vHIT, video head impulse test

See also: Vestibulo-ocular reflex (VOR)

Inferior olive☆ Bookmark

A brainstem nucleus involved in motor learning that sends climbing fibers to the cerebellum for VOR recalibration.

See also: Climbing fibers

Irregular afferents☆ Bookmark

Primary vestibular neurons with variable discharge and high dynamic sensitivity, connected to Type I hair cells and tuned to rapid motion.

See also: Afferent neurons, Hair cells

Neural integrator☆ Bookmark

A network in the prepositus hypoglossi, vestibular nuclei, and cerebellum that converts eye-velocity signals into position commands to hold gaze.

See also: Burst-tonic (BT) neurons

Otoconia☆ Bookmark

Calcium carbonate crystals resting on the otolithic membrane; their inertia drives hair-cell deflection during linear motion.

Also: otoliths, otoconial crystals

See also: Otolith organs

Otolith organs☆ Bookmark

The utricle and saccule, which sense linear acceleration and head tilt with respect to gravity.

Also: utricle, saccule, maculae

See also: Otoconia

Purkinje cells☆ Bookmark

The principal inhibitory neurons of the cerebellar cortex, modulating vestibular nucleus output based on cerebellar inputs.

See also: Climbing fibers

Retinal slip☆ Bookmark

The motion of an image across the retina, detected as an error signal used to adapt and recalibrate the VOR.

See also: Vestibulo-ocular reflex (VOR), Climbing fibers

Semicircular canals☆ Bookmark

Three orthogonal fluid-filled tubes — horizontal, anterior, posterior — that sense angular acceleration of the head.

Also: horizontal canal, anterior canal, posterior canal

See also: Angular acceleration, Velocity storage mechanism

Velocity storage mechanism☆ Bookmark

A central circuit that prolongs the VOR response beyond the physical stimulus, mediated by the vestibular nuclei and cerebellum.

See also: Semicircular canals, Vestibulo-ocular reflex (VOR)

Vestibular nuclei (VN)☆ Bookmark

Brainstem nuclei — superior, medial, lateral, inferior — that receive labyrinthine afferent input and modulate vestibular reflexes.

Also: VN

Vestibulo-ocular reflex (VOR)☆ Bookmark

A reflex that stabilizes images on the retina during head movement by producing compensatory eye movements.

Also: VOR

See also: Retinal slip, Velocity storage mechanism, Head impulse test (HIT)

Vestibulospinal reflex (VSR)☆ Bookmark

A reflex that controls postural muscles in response to vestibular input to maintain balance and orientation.

Also: VSR