Cervical dystonia (CD) is a neurological disorder characterized by abnormal movements and postures of the head. The brain regions responsible for these abnormal movements are not well understood, because most imaging techniques for assessing regional brain activity cannot be used when the head is moving. Recently, we mapped brain activation in healthy individuals using functional magnetic reson...

The present study focused on the movements that owls perform before they swoop down on their prey. The working hypothesis was that owl head movements reflect the capacity to efficiently follow visually and auditory a moving prey. To test this hypothesis, five tame barn owls (Tyto alba) were each exposed 10 times to a live vole in a laboratory setting that enabled us to simultaneously record the...

Limb movement is smooth and corrections of movement trajectory and amplitude are barely noticeable midflight. This suggests that skeletomuscular motor commands are smooth in transition, such that the rate of change of acceleration (or jerk) is minimized. Here we applied the methodology of minimum-jerk submovement decomposition to a member of the skeletomuscular family, the head movement. We exa...

Hitters in fast ball-sports do not align their gaze with the ball throughout ball-flight; rather, they use predictive eye movement strategies that contribute towards their level of interceptive skill. Existing studies claim that (i) baseball and cricket batters cannot track the ball because it moves too quickly to be tracked by the eyes, and that consequently (ii) batters do not - and possibly ...

It has been unclear whether the perception of depth from motion parallax is an entirely visual process or whether it requires extra-retinal information such as head movements, vestibular activation, or eye movements. Using a motion aftereffect and static test stimulus technique to eliminate visual cues to depth, this psychophysical study demonstrates that the visual system employs a slow eye mo...

During performance of natural tasks subjects sometimes Wxate objects that are manipulated several seconds later. Such early looks are known as “look-ahead Wxations” (Pelz and Canosa in Vision Res 41(25–26):3587–3596, 2001). To date, little is known about their function. To investigate the possible role of these Wxations, we measured Wxation patterns in a model-building task. Subjects assembled ...

A horizontally moving target was followed by rotation of the eyes alone or by a lateral movement of the head. These movements resulted in the retinal displacement of a vertically moving target from its perceived path, the amplitude of which was determined by the phase and amplitude of the object motion and of the eye or head movements. In two experiments, we tested the prediction from our model...

Introduction:  Stereotactic  radiosurgery  is  a  technique  for  the  treatment  of  intracranial  lesions  with  highly  collimated  x-ray  beam.  Linac-based  radiosurgery  is  currently  performed  by  two  techniques:  couch or pedestal mounted. In the first technique, a device is required to affix patient's head to a couch  and  moreover  to  translate  it  accurately.  Structure  of  suc...