This study was motivated by the observation of early head movements (EHMs) occasionally generated before gaze shifts. Human subjects were presented with a visual or auditory target, along with an accompanying stimulus of the other modality, that either appeared at the same location as the target (enhancer condition) or at the diametrically opposite location (distractor condition). Gaze shifts g...

When the head is unrestrained, rapid displacements of the visual axis-gaze shifts (eye-re-space)-are made by coordinated movements of the eyes (eye-re-head) and head (head-re-space). To address the problem of the neural control of gaze shifts, we studied and contrasted the discharges of omnipause neurons (OPNs) during a variety of combined eye-head gaze shifts and head-fixed eye saccades execut...

The present study investigated the gaze as well as the head and the eye-in-head movements of neglect patients while they were exploring their surroundings. A random configuration of letters was presented on the inner surface of a sphere that surrounded the subject, requiring free exploratory eye and head movements. The subjects were requested to search for a single (non-existent) target letter....

In oculomotor research, there are two common methods by which the apparent location of visual and/or auditory targets are measured, saccadic eye movements with the head restrained and gaze shifts (combined saccades and head movements) with the head unrestrained. Because cats have a small oculomotor range (approximately +/-25 degrees), head movements are necessary when orienting to targets at th...

We investigated coordinated movements between the eyes and head ("eye-head coordination") in relation to vision for action. Several studies have measured eye and head movements during a single gaze shift, focusing on the mechanisms of motor control during eye-head coordination. However, in everyday life, gaze shifts occur sequentially and are accompanied by movements of the head and body. Under...

Cervical dystonia is characterized by abnormal posturing of the head, often combined with tremor-like oscillatory head movements. The nature and source of these oscillatory head movements is controversial, so they were quantified to delineate their characteristics and develop a hypothetical model for their genesis. A magnetic search coil system was used to measure head movements in 14 subjects ...

An important prerequisite for effective motor action is the discrimination between active and passive body movements. Passive movements often require immediate reflexes, whereas active movements may demand suppression of the latter. The vestibular system maintains correct body and head posture in space through reflexes. Since vestibular inputs have been reported to be largely suppressed in the ...

Two experiments were conducted in order to determine the patterns of transfer of visuomotor adaptation between arm and head pointing. An altered gain of display of pointing movements was used to induce a conflict between visual and somatosensory representations. Two subject groups participated in Experiment 1: group 1 adapted shoulder pointing movements, and group 2 adapted wrist pointing movem...

The firing behavior of 51 non-eye movement related central vestibular neurons that were sensitive to passive head rotation in the plane of the horizontal semicircular canal was studied in three squirrel monkeys whose heads were free to move in the horizontal plane. Unit sensitivity to active head movements during spontaneous gaze saccades was compared with sensitivity to passive head rotation. ...

OBJECTIVE To determine the contribution of central preprogramming of eye movements to dynamic visual acuity (DVA) during head movement in patients with vestibular hypofunction. STUDY DESIGN Prospective, clinical study. SETTING Tertiary care, academic hospitals. PARTICIPANTS Twenty-six healthy subjects and 20 patients with unilateral (UVL) and 7 with bilateral vestibular loss (BVL) (age ra...