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  • 1
    Electronic Resource
    Electronic Resource
    Single cell activity in area 18 of the cat's visual cortex during optokinetic nystagmus (1984)
    Springer
    Experimental brain research 57 (1984), S. 118-127 
    Details
    ISSN: 1432-1106
    Keywords: Cat's area 18 ; Optokinetic nystagmus ; Velocity tuning ; Corollary discharge ; Saccadic facilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single cell activity was recorded in area 18 during optokinetic nystagmus (OKN) in awake cats. The search coil technique was used to record the horizontal and vertical eye movements. Cells showing direction specific responses to a moving large area random dot pattern (70%) were tested with different velocities in the preferred and in the null-direction. Their response characteristics can be classified according to the two phases of the OKN. 41% responded specifically to the retinal slip velocity, having their response optimum at different values between 2 and 100°/s. Additionally, in 60% of all tested cells the resetting saccades of the OKN were correlated with brief activity bursts of 39 ms latency on the average. These results are discussed in terms of two concepts: the classic concept of a corollary discharge from the oculomotor system and the concept of a gating function of the reticular system on thalamic and cortical transmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231138
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Eye movements elicited by transparent stimuli (1994)
    Springer
    Experimental brain research 98 (1994), S. 314-322 
    Details
    ISSN: 1432-1106
    Keywords: Transparency ; Smooth pursuit ; Optokinetic nystagmus ; Antagonistic OKN ; Dichoptic presentation ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A transparent motion condition occurs when two different motion vectors appear at the same region of an image. Such transparency during self-motion has shown demonstrable effects on perception and on the underlying neurophysiology in the cortical and subcortical structures of primates. Presumably such stimulus conditions also influence oculomotor behavior. We investigated smooth-pursuit performance, using a transparent stimulus consisting of two oppositely-moving patterns. We found slight reduction in the mean eye velocity tracking a transparent pattern, compared with that when tracking a unidirectional pattern. Additionally, we investigated the behavior of the optokinetic system to transparency, demonstrating that it elicits antagonistic optokinetic nystagmus, with distinctly reduced gain of the slow phases. Furthermore, we observed, during optokinetic stabilization of transparent stimuli, directional dominances demonstrating that subjects preferably followed one direction. Presenting a transparent stimulus with oppositely moving patterns and different velocities we found a general velocity dominance demonstrating that patterns with a certain velocity are preferred. Performing all experiments under dichoptic conditions produced results comparable with those found under transparent stimulus conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228419
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of early monocular deprivation on visual input to cat nucleus of the optic tract (1983)
    Springer
    Experimental brain research 51 (1983), S. 236-246 
    Details
    ISSN: 1432-1106
    Keywords: Nucleus of the optic tract ; Monocular deprivation ; Visual responses ; Optokinetic nystagmus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single cells were recorded extracellularly in the nucleus of the optic tract (NOT) in monocularly deprived cats. Monocular deprivation had no effect on the direction specificity of these neurons, i.e. all cells in the left nucleus preferred movements from right to left and all units in the right nucleus preferred movements from left to right in the visual field. Neurons driven from the deprived eye failed to respond to stimuli moving at velocities above 10°/s whereas neurons driven from the non-deprived eye responded to velocities up to and above 100°/s as do neurons in normal cats. In 8 out of the 10 cats tested all cells in the two nuclei could be influenced only from the contralateral eye irrespective whether this was the deprived or the non-deprived eye. In the other two cats the influence from the non-deprived eye on cells in the ipsilateral NOT was found to be normal. This influence is mediated probably via cortico-fugal projections. In the 8 abnormal cats a clear deprivation effect could be assigned for the first time to the non-deprived eye consisting in a loss of its connections to the ipsilateral NOT. Electrical stimulation of the visual cortex revealed, however, the existence of a connection between the visual cortex and the NOT. A possible explanation for the specific deficit with visual stimulation in the cortico-pretectal synapse ipsilateral to the non-deprived eye is discussed in relation to developmental mechanisms. The conduction velocity of retinal input to the NOT and the output of the NOT to the inferior olive remained uninfluenced by visual deprivation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237199
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    A quantitative analysis of the direction-specific response of neurons in the cat's nucleus of the optic tract (1981)
    Springer
    Experimental brain research 42 (1981), S. 146-157 
    Details
    ISSN: 1432-1106
    Keywords: Nucleus tractus opticus ; Visual response ; Direction specificity ; Optokinetic nystagmus ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary All cells in the nucleus of the optic tract (NOT) of the cat, that Bcould be activated antidromically from the inferior olive, were shown to be direction-specific, as influenced by horizontal movements of an extensive visual stimulus. Cells in the left NOT were activated by leftward and inhibited by rightward movement, while those in the right NOT were activated by rightward and inhibited by leftward movement. Vertical movements did not modulate the spontaneous activity of the cells. The mean spontaneous discharge rate in 50 NOT cells was 30 spikes/s. This direction-specific response was maintained over a broad velocity range (〈0.1 ° – 〉100 °/s). Velocities over 200 °/s could inhibit NOT cells regardless of stimulus direction. All cells in the NOT were driven by the contralateral eye, about half of them by the ipsilateral eye also. In addition, activation through the contralateral eye was stronger in most binocular units. Binocular cells preferred the same direction in the visual space through both eyes. An area approximately corresponding to the visual streak in the cat's retina projected most densely onto NOT cells. This included an extensive ipsilateral projection. No clear retinotopic order was seen. The most sensitive zone in the very large receptive fields (most diameters being 〉20 °) was along the horizontal zero meridian of the visual field. The retinal input to NOT cells was mediated by W-fibers. The striking similarities between the input characteristics of NOT-cells and optokinetic nystagmus are discussed. The direction selectivity and ocular dominance of the NOT system as a whole can provide a possible explanation for the directional asymmetry in the cat's optokinetic nystagmus when only one eye is stimulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236901
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    Paper (German National Licenses)
    Fulltext
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