Vestibulo-ocular reflex.

The vestibulo-ocular reflex (VOR) ensures best vision during head motion by moving the eyes contrary to the head to stabilize the line of sight in space. The VOR has three main components: the peripheral sensory apparatus (a set of motion sensors: the semicircular canals, SCCs, and the otolith organs), a central processing mechanism, and the motor output (the eye muscles). The SCCs sense angular acceleration to detect head rotation; the otolith organs sense linear acceleration to detect both head translation and the position of the head relative to gravity.

Saccade velocity is controlled by polyglutamine size in spinocerebellar ataxia 2.

We assessed maximal saccade velocity (MSV) in 82 spinocerebellar ataxia type 2 (SCA2) patients and 80 controls, correlating it to disease duration, polyglutamine expansion size, age at onset, ataxia score, age, and sex. Little overlap with normal values was found even at earliest stages. Stepwise linear regression analysis showed that 60-degree MSV was strongly influenced by polyglutamine size and less by disease duration, whereas the reverse was found for ataxia score.

Cortical vestibular representation in the superior temporal gyrus.

We present the unique case of a patient with a circumscribed solitary cerebral metastasis of a malignant melanoma extending from the medial part of the superior temporal gyrus to the lower part of the 1st long insular gyrus causing gait and stance instability and an ipsiversive tilt of the subjective visual vertical. Oculomotor disorders could not be detected. We suggest that the superior temporal gyrus is likely to be involved in spatial orientation presumably using otolithic information.