نتایج جستجو برای: optokinetic nystagmus
تعداد نتایج: 4674 فیلتر نتایج به سال:
background: neurotologic signs and symptoms, especially vestibular symptoms are common in migrainous patients. involvement of the visual system in migrainures has received a great deal of attention in recent years, but the oculomotor part of the visual system has been largely ignored. the goal of this study was to investigate some parts of the central vestibular system using the oculomotor part...
Optokinetic afternystagmus follows optokinetic nystagmus as an expression of the central velocity storage integrator discharge and its fast phase is beating in the same direction as the previous optokinetic nystagmus. We investigated the correlation between vestibulo-ocular reflex and optokinetic afternystagmus in normal subjects and in patients with bilateral vestibular disorders. The aim of t...
A severe defect of optokinetic nystagmus (OKN) was found in 46 patients with congenital nystagmus. Abnormal patterns of OKN, such as superimposition of pendular oscillations on the optokinetic slow component and inversion of OKN, were observed. Optokinetic gain (eye movement velocity/drum velocity) was decreased compared to that in normal subjects, and optokinetic after-nystagmus, or transient ...
Eye movements were recorded in the pigmented rat during vestibular, optokinetic and combined visual-vestibular stimulation. The dominant time constant in pigmented rats, tested during angular vestibular stimulation in darkness, is about two times longer than the cupular time constant. The gain and the duration of nystagmus, achieved by angular vestibular stimulation, can be enhanced by visual i...
Purpose: To evaluate saccadic and pursuit ocular movements and optokinetic nystagmus in adults, analyzing the effect of age and visual alterations. Methods: We evaluated 40 subjects of both genders, aged 20–49 years, with no auditory or vestibular complaints and who presented a normal basic audiology evaluation, absence of spontaneous nystagmus with open eyes, semi-spontaneous nystagmus, and sp...
Uniform motion across the retina is a powerful cue to the perception of self-motion. In spite of its importance for adaptive functioning, little is known about the early development of uniform motion sensitivity. Six-, 12-, and 18-week-old infants viewed random-dot kinematograms depicting leftward or rightward uniform motion. The display induced optokinetic nystagmus (OKN), which a trained obse...
Currently, the vestibulo-ocular and optokinetic reflexes are both thought to require a velocity storage mechanism within their neural pathways. To test whether these storage mechanisms are shared by both reflexes, animals were given programs of stimulation known to change the status of the storage mechanism of one of the type of nystagmus. The other type of nystagmus was examined then to ascert...
Optokinetic nystagmus (OKN) can be demonstrated from birth, but behavioural discrimination tasks such as habituation and preferential looking do not reveal any sensitivity to motion direction until a few weeks of age. This study compared coherence threshold for motion direction for OKN and preferential looking responses using closely comparable stimuli, in infants between 6 and 27 weeks of age....
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