Neck function in rhythmic jaw activities. Birgitta Häggman Henrikson 2004. Department of Odontology, Clinical Oral Physiology, Umeå University, and Centre for Musculoskeletal Research, Gävle University, Sweden. Previous studies in animals and humans show anatomic and physiological connections between the trigeminal and the cervical regions. This investigation tested the hypothesis of a function...

Until now, most studies concerning active head movements in three dimensions have used the classical rotation vector description. Although this description yields both the orientation of the head rotation axis and the amount of rotation, it is incomplete because it cannot specify the location of this rotation axis in space. The latter is of importance for a proper picture of the vestibular cons...

Our goal is to review vestibulo-oculomotor reflex (VOR) studies on several peripheral vestibular disorders (Ménière's disease, vestibular neuritis, benign paroxysmal positional vertigo, superior canal dehiscence syndrome, and vestibular neuroma), using the scleral search coil (SSC) technique. Head movements are detected by vestibular receptors and the elicited VOR is responsible for compensator...

Visual acuity and motion perception are degraded during head movements unless the eyes counter-rotate so as to stabilize the line of sight and the retinal image. The vestibulo-ocular reflex (VOR) is assumed to produce this ocular counter-rotation. Consistent with this assumption, oscillopsia is a common complaint of patients with bilateral vestibular weakness. Shanidze et al. recently described...

The superior colliculus (SC) is a multilayered structure in the mammalian midbrain. Even though the behavioral function of the SC has been studied for well over 30 yr, it continues to be a source of surprising new findings. Traditionally it has been assumed that the primate SC selects and generates saccadic eye movements. However, more recent experiments in head-free monkeys suggested instead t...

We analyzed gaze shifts made by trained rhesus monkeys with completely unrestrained heads during performance of a delayed gaze shift task. Subjects made horizontal, vertical, and oblique gaze shifts to visual targets. We found that coordinated eye-head movements are characterized by a set of lawful relationships, and that the initial position of the eyes in the orbits and the direction of the g...

PURPOSE Recent research on head shake posturography has demonstrated a modest increase in sensitivity to identifying peripheral vestibular system asymmetry when horizontal head movements were added to portions of the standard Sensory Organization Test (SOT) battery. However, limitations with respect to the head shake protocol were outlined, and usable data for assessing performance could not be...

Simple activities like picking up the morning newspaper or catching a ball require finely coordinated movements of multiple body segments. How our brain readily achieves such kinematically complex yet remarkably precise multijoint movements remains a fundamental and unresolved question in neuroscience. Many prevailing theoretical frameworks ensure multijoint coordination by means of integrative...

Calendrical savants can name the weekdays for dates from different years with remarkable speed and accuracy. Whether calculation rather than just memory is involved is disputed. Grounds for doubting whether they can calculate are reviewed and criteria for attributing date calculation skills to them are discussed. At least some calendrical savants possess date calculation skills. A behavioural c...

During conversation, women tend to nod their heads more frequently and more vigorously than men. An individual speaking with a woman tends to nod his or her head more than when speaking with a man. Is this due to social expectation or due to coupled motion dynamics between the speakers? We present a novel methodology that allows us to randomly assign apparent identity during free conversation i...