By stimulating the ear with air-conducted sound or bone-conducted vibration stimuli, vestibular-evoked myogenic potential (VEMP) can be recorded on the contracted neck muscles, termed cervical VEMP (cVEMP), and on the extraocular muscles, termed ocular VEMP (oVEMP). These two electrophysiological tests expand the test battery for clinicians to explore the dynamic otolithic function, adding a po...

The observation that the amplitude of ves­ tibular nystagmus grows as gaze is increased in the direction of the nystagmus fast phase and diminished with gaze in the opposite direction is known as "Alexander's law". We have developed an analog computer model to simulate Alexander's law in nys­ tagmus secondary to dysfunction of a semicircular canal. The model utilizes relevant brainstem anatomy ...

Despite nearly perfect gaze stability during natural head movements, the amplitude of the vestibulo-ocular reflex during passive head and body translation (TVOR) has been consistently reported to be undercompensatory during near target viewing. Here we have compared the rhesus monkey TVOR during pure head and body translation with the eye movements generated during eccentric yaw rotations, wher...

Growing experimental and theoretical evidence suggests a functional synergy in the processing of otolith and semicircular canal signals for the generation of the vestibulo-ocular reflexes (VORs). In this study we have further tested this functional interaction by quantifying the adaptive changes in the otolith-ocular system during both rotational and translational movements after surgical inact...

The influence of bilateral plugs of the anterior and posterior semicircular canals (ASCs, PSCs) on the vertical vestibuloocular reflex (VVOR-0) of the rabbit, oscillated about the longitudinal axis maintained in a horizontal orientation, was studied. Bilateral plugs of either the ASCs or PSCs reduced the gain of the VVOR-0 evoked by stimulus frequencies above 0.005 Hz, but left a residual gain ...

For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using...

In jawed (gnathostome) vertebrates, the inner ears have three semicircular canals arranged orthogonally in the three Cartesian planes: one horizontal (lateral) and two vertical canals. They function as detectors for angular acceleration in their respective planes. Living jawless craniates, cyclostomes (hagfish and lamprey) and their fossil records seemingly lack a lateral horizontal canal. The ...

On the basis of dissection of 24 bones of 12 black rats a systematic anatomical description was made and measurements of selected size parameters of the temporal bone were taken. Besides the main air space in the middle ear, the tympanic bulla, there are also additional air cells, namely the anterior and posterior epitympanic recesses, containing the head of the malleus and the body of the incu...

INTRODUCTION The vestibular system detects and encodes changes in angular and linear accelerations of the head. This information is then used in a broad repertoire of vertebrate motor behaviors essential for survival. We are trying to understand some of the underlying mechanisms of vestibular function by studying components of the vestibulocollic reflex (VCR), one of the most basic mechanisms b...

Galvanic vestibular stimulation (GVS) is a simple, safe, and specific way to elicit vestibular reflexes. Yet, despite a long history, it has only recently found popularity as a research tool and is rarely used clinically. The obstacle to advancing and exploiting GVS is that we cannot interpret the evoked responses with certainty because we do not understand how the stimulus acts as an input to ...