Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
  • 2
    ISSN: 1432-1459
    Keywords: Key words Eye movements ; Saccades and visual exploration ; Smooth-pursuit eye movements ; Ethanol ; Alcohol consumption ; Infrared photoelectric technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Horizontal and vertical eye movements were recorded and analysed with an infrared photoelectric technique in 12 healthy volunteers under various blood alcohol concentrations (0.0, 0.5, 1.0 g/kg body weight, [‰]). The predictive smooth-pursuit tracking and saccadic eye movements were studied in response to unpredictable target jumps and during scanning of a classical kitchen scene and a traffic scene. Smooth-pursuit eye movement gain value decreased dose-dependently and was compensated by an increased number of catch-up saccades. With increasing blood alcohol concentrations peak velocities of horizontal and vertical visually guided reflexive saccades decreased while their latencies to the target increased. At blood alcohol concentrations of 0.5‰ and 1.0‰ healthy volunteers showed significantly longer mean fixation durations and a lower total number of exploratory saccades when scanning both the classical kitchen scene and the traffic scene. Surprisingly, in both of these scanning tasks the total fixation duration or the relative number of exploratory saccades increased in those scene sectors in which exciting situations were presented. Additionally, the time interval needed to foveate these exciting areas for the first time increased, probably due to an attention deficit. In conclusion, these findings indicate that alcohol consumption impairs the velocity and initiation of saccadic and smooth-pursuit eye movements, but that subjects can nevertheless still recognize exciting and relevant areas of visual scenes. The significant increase in fixation time, however, does not allow scanning of the entire visual scene during an adequate period of time. Therefore the reduced visual exploration caused by alcohol reflects an impaired sensorimotor processing of active visual perception.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1459
    Keywords: Key words Autosomal-dominant cerebellar ataxia ; Spinocerebellar ; atrophy type 1 ; Slow saccades ; Electro-oculography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to study the relation between genotype and phenotype, a detailed study of the course of oculomotor deficits was performed in three patients with autosomal-dominant cerebellar ataxia, subtype spinocerebellar atrophy type 1 (SCA 1) using clinical testing and electrooculography. DNA analysis revealed a CAG repeat expansion of 65 in the SCA 1 gene on chromosome 6p in all patients. A progressive disorder of the saccadic system became obvious, leading to a marked slowing of saccadic eye movements and loss of pathological and physiological nystagmus. An upward gaze palsy developed early, followed by horizontal and downward gaze palsy at a later state of the disease. Smooth pursuit eye movements were disturbed to a lesser extent; the vestibulo-ocular reflex was reduced. As an additional feature, severe loss of visual acuity developed due to progressive optic nerve atrophy. The oculomotor deficits can be explained by progressive damage to the brain stem rather than to the cerebellum. Each combination of oculomotor deficits with or without optic atrophy may occur irrespective of the gene locus of the disease, making a correlation between clinical signs and genetic findings difficult.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Smooth pursuit eye movements are evoked by retinal image motion of visible moving objects and can also be driven by the internal representation of a target due to extraretinal mechanisms (e.g. efference copy). To delineate the corresponding neuronal correlates, functional magnetic resonance imaging at 1.5 T was applied during smooth pursuit at 10 °/s with continuous target presentation and target blanking for 1 s to 16 right-handed healthy males. Eye movements were assessed during scanning sessions by infra-red reflection oculography. Smooth pursuit performance was optimal when the target was visible but decreased to a residual velocity of about 30% of the velocity observed during continuous target presentation. Random effects analysis of the imaging data yielded an activation pattern for smooth pursuit in the absence of a visual target (in contrast to continuous target presentation) which included a number of cortical areas in which extraretinal information is available such as the frontal eye field, the superior parietal lobe, the anterior and the posterior intraparietal sulcus and the premotor cortex, and also the supplementary and the presupplementary eye field, the supramarginal gyrus, the dorsolateral prefrontal cortex, cerebellar areas and the basal ganglia. We suggest that cortical mechanisms such as prediction, visuo-spatial attention and transformation, multimodal visuomotor control and working memory are of special importance for maintaining smooth pursuit eye movements in the absence of a visible target.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...