Fish otolith and water chemistry were assessed in the Grand Canyon reach of the Colorado River and its tributaries. Aqueous strontium and selenium (in ratio to calcium) and carbon stable isotopic ratios were identified as markers with excellent potential to track the provenance and movements of the endangered humpback chub Gila cypha. Although otolith dC and Sr/Ca varied proportionately to wate...

A common goal of the translational vestibuloocular reflex (TVOR) and the rotational vestibuloocular reflex (RVOR) is to stabilize visual targets on the retinae during head movement. However, these reflexes differ significantly in their dynamic characteristics at both sensory and motor levels, implying a requirement for different central processing of canal and otolith signals. Semicircular cana...

Experiments were conducted to understand the effects of thyroid hormones and thiourea (TU) on otolith growth during metamorphosis of leptocephali. TU is an anti-thyroid hormone drug that inhibits the production of thyroxine (T4) and triiodothyronine (T3) in the thyroid tissue. Fully grown leptocephali of tarpon Megalops cyprinoides collected at the mouth of the Gong-Shy-Tyan Brook, N Taiwan, we...

1. The dynamic contribution of otolith signals to three-dimensional angular vestibuloocular reflex (VOR) was studied during off-vertical axis rotations in rhesus monkeys. In an attempt to separate response components to head velocity from those to head position relative to gravity during low-frequency sinusoidal oscillations, large oscillation amplitudes were chosen such that peak-to-peak head ...

To compare and contrast the neural mechanisms that contribute to vestibular perception and action, we measured vestibuloocular reflexes (VOR) and perceptions of tilt and translation. We took advantage of the well-known ambiguity that the otolith organs respond to both linear acceleration and tilt with respect to gravity and investigated the mechanisms by which this ambiguity is resolved. A new ...

Horizontal and vertical smooth pursuit was compared with otolith-ocular responses in 11 patients with cerebellar ataxia and 21 normal subjects using three-dimensional magnetic search coil eye movement recordings. Otolith-ocular responses were investigated during off-vertical axis rotation. This stimulus induces nystagmus consisting of the exponentially decaying canalicular response, and an eye-...

Evaluating the function of the vestibular part of the inner ear comprises more than the classic analysis of the lateral semicircular canal function. In healthy subjects, positional alcohol nystagmus may be seen after acute alcohol ingestion. Posturography has shown a deteriorated equilibrium after even moderate doses of alcohol, which speculatively could be an effect of otolith disturbance or a...

To investigate the neural mechanisms that humans use to process the ambiguous force measured by the otolith organs, we measured vestibuloocular reflexes (VORs) and perceptions of tilt and translation. One primary goal was to determine if the same, or different, mechanisms contribute to vestibular perception and action. We used motion paradigms that provided identical sinusoidal inter-aural otol...

It has been well documented that vestibular-mediated cardiovascular regulation plays an important role in maintaining stable blood pressure (BP) during postural changes. But the underlying neural mechanisms remain to be elucidated. In particular, because the vestibular stimulation employed in previous animal studies activated both semicircular canals and otolith organs, the contributions of the...

We tested the hypothesis that strontium:calcium (Sr:Ca) in otoliths are reflective of environmental salinity experienced by two estuarine fishes during early life. Laboratory and field experiments were performed to examine the effects of salinity and temperature on Sr:Ca in otoliths of black drum (Pogonias cromis) and red drum (Sciaenops ocellatus). Otolith Sr:Ca of juveniles reared at four sal...