The effects of lesions of the nucleus of optic tract on the optokinetic nystagmus in monkeys.

1. Total optokinetic responses measured by electro-oculography and single unit recordings from the nucleus of the optic tract and dorsal terminal nucleus (NOT-DTN) of the accessory optic system were taken from young adult wallabies, whose one eye had been rotated about the optic axis at birth, and were compared with those from normal controls. 2. The velocities of the horizontal component of the slow phases of optokinetic nystagmus were measured in the horizontal plane as a function of the direction of stimulus motion. In normal animals the overall gain during monocular stimulation was greatest for horizontal temporonasal movement, with a lesser response to movement in the opposite, nasotemporal, direction. Upward or downward vertical stimulus motion did not elicit horizontal responses. In animals where one eye was removed at birth and the other eye was normal, the characteristic bidirectional response was retained; the response was identical with that elicited from one eye of a normal animal. 3. After surgical rotation (extorsion) of the left eye by approximately 90 degrees on or within a few days of birth, the animals were grown to adulthood. The visual streak of the retina of the operated eye was then found, in individual cases, to be between 30-100 degrees from horizontal with the head held in the standard resting position. This angle was taken as the definitive degree of cyclotorsion resulting from the operation in each animal. The extraocular muscles connected with regions of the eye adjacent to the location of their outgrowth in the orbit and not with the normal point of attachment on the globe.(ABSTRACT TRUNCATED AT 250 WORDS)

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Optokinetic nystagmus in cats with congenital strabismus

Journal of Neurophysiology ◽

10.1152/jn.1996.75.4.1495 ◽

1996 ◽

Vol 75 (4) ◽

pp. 1495-1502 ◽

Cited By ~ 11

Author(s):

K. P. Hoffmann ◽

C. Distler ◽

C. Markner

Keyword(s):

Visual Cortex ◽

Eye Movements ◽

Closed Loop ◽

Optokinetic Nystagmus ◽

Optic Tract ◽

Open Loop ◽

Differential Analysis ◽

Accessory Optic System ◽

Symmetry Index ◽

Pretectal Nucleus

1. Eye movements were recorded in seven innately esotropic cats during monocular and binocular horizontal optokinetic stimulation, using the search coil technique in five cats and electrooculography in two cats. 2. During closed loop measurements in these strabismic cats, slow phases of optokinetic nystagmus (OKN) were characterized by an overall reduced gain when compared with normal controls. In addition, response gain to monocular nasotemporal stimulation was even more reduced than that to temporonasal stimulation, resulting in an increased asymmetry of closed loop gain. 3. During open loop measurements, eye velocity in strabismic cats was very low at all velocities tested. 4. Differential analysis of the symmetry of OKN revealed that all our strabismic cats had a "good" or more symmetric and a "poor" or more asymmetric eye. In addition, when analyzed separately at individual velocities, the symmetry index of the good eye was fairly constant over the velocity range tested. By contrast, the symmetry index of the poor eye dropped dramatically at higher stimulus velocities. 5. To analyze the relationship of OKN symmetry and cortical physiology, we calculated the ratio between the percentage of neurons driven by one eye in the ipsilateral and the contralateral cortical hemisphere. We found a weak correlation between OKN symmetry and this cortical symmetry index (P < 0.05, analysis of variance). 6. In conclusion, slow eye movements in cats with congenital esotropia are characterized by extremely low gain, especially at higher stimulus velocities. In addition, OKN symmetry during monocular stimulation is decreased. Our data suggest that OKN symmetry is weakly correlated with the proportion of binocular neurons in the visual cortex ipsilateral to the stimulated eye. However, OKN characteristics seem to reflect to a higher degree the response properties of neurons in the pretectal nucleus of the optic tract and the dorsal terminal nucleus of the accessory optic system than properties of neurons in the visual cortex.

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Role of the nucleus of the optic tract of monkeys on optokinetic nystagmus and optokinetic after-nystagmus: Effects of lesions

Neuroscience Research Supplements ◽

10.1016/0921-8696(88)90191-0 ◽

1988 ◽

Vol 7 ◽

pp. S90

Author(s):

Tomohiko Hasegawa ◽

Koji Harada ◽

Takao Ikarashi ◽

Isao Kato

Keyword(s):

Optokinetic Nystagmus ◽

Optic Tract

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Lesions of the Nucleus of the Optic Tract Affect Two Components of Optokinetic Nystagmus.

Equilibrium Research ◽

10.3757/jser.52.474 ◽

1993 ◽

Vol 52 (3) ◽

pp. 474-478

Author(s):

Isao Kato ◽

Shoji Watanabe ◽

Hiroaki Nakajima ◽

Isamu Takeyama ◽

Tomohiko Hasegawa

Keyword(s):

Optokinetic Nystagmus ◽

Optic Tract

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The paths and destinations of the induced ipsilateral retinal projection in goldfish

Development ◽

10.1242/dev.45.1.145 ◽

1978 ◽

Vol 45 (1) ◽

pp. 145-159

Author(s):

Stephen S. Easter ◽

John T. Schmidt ◽

Steven M. Leber

Keyword(s):

Optokinetic Nystagmus ◽

Optic Tract ◽

Behavioral Study ◽

Retinal Projection ◽

Intact Side ◽

Optic Fibers ◽

The Brain ◽

Retinal Fibers

Adult goldfish had one tectal lobe removed surgically, and several months later, the eye contralateral to the missing tectum was injected with radioactive proline. Radioautographs of the brains were studied to trace the paths and termination sites of the optic fibers. The optic tract decussated at the chiasm, as normally, but then ran caudally in a large neuroma on the tectum-less side of the brain. Substantial numbers of fibers left this neuroma to enter two or more of five commissures, through which they recrossed the midline. These commissures: transverse, minor, horizontal, posterior and ansate, ordinarily contain few or no optic fibers. All are normally linked with the tectum. Negligible numbers of aberrant optic fibers recrossed the midline elsewhere. On the intact side of the brain, ipsilateral to the injected eye, the optic fibers innervated some or all of the nuclei and areas normally served by contralateral retinal fibers. An earlier behavioral study of these same fish had shown that some of them made reversed optokinetic nystagmus in response to stripe movement seen by the eye projecting ipsilaterally; others failed to respond to stimuli through this eye. In all the reversed responders, a caudal group of retinal projection sites was labeled ipsilaterally. This included the basal optic nucleus and the caudal portions of nucleus dorsolateralis thalami and area pretectalis. Tn the non-responders, these targets were not labeled ipsilaterally. Together, these results suggest that one or more of these three sites is or are responsible for optokinetic nystagmus in normal goldfish.

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A comparison of optokinetic nystagmus and cell morphology of the nucleus of the optic tract in pigmented and albino rats

Behavioural Brain Research ◽

10.1016/0166-4328(85)90123-8 ◽

1985 ◽

Vol 16 (2-3) ◽

pp. 208-209

Author(s):

K. Hofstetter ◽

K.-P. Hoffmann

Keyword(s):

Cell Morphology ◽

Optokinetic Nystagmus ◽

Optic Tract ◽

Albino Rats

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Neurons of the medial terminal accessory optic nucleus of the rat are poorly collateralized

Visual Neuroscience ◽

10.1017/s0952523800001188 ◽

1989 ◽

Vol 2 (3) ◽

pp. 269-273 ◽

Cited By ~ 8

Author(s):

R. J. Clarke ◽

R. A. Giolli ◽

R. H. Blanks ◽

Y. Torigoe ◽

J. H. Fallon

Keyword(s):

Optokinetic Nystagmus ◽

Inferior Olive ◽

Previous Analysis ◽

Optic Tract ◽

Vestibular Nuclei ◽

The Other ◽

Projection Neurons ◽

Double Labeling ◽

Cell Counts ◽

Brainstem Nuclei

AbstractThe vast majority of neurons of the rat medial terminal nucleus (MTN) project to the nucleus of the optic tract (NOT), but the MTN also projects to a lesser degree upon a number of other brainstem nuclei controlling optokinetic nystagmus. Because of the diversity of targets of the MTN, it is possible that individual neurons have branched axons that project to two or more brainstem nuclei. The possibility that axons of MTN-NOT neurons collateralize to innervate other MTN targets is examined in the rat with the fluorescent, double-labeling, retrograde tracer technique. Fluoro-Gold was injected into the NOT while Fast Blue was simultaneously injected into each of five other known targets of the MTN: the supraoculomotor-periaqueductal gray; the dorsal cap of the inferior olive; the visual tegmental relay zone; the dorsolateral nucleus of the basal pons; and the superior/lateral vestibular nuclei. Brainstem sections were processed for fluorescence microscopy and the MTN was examined for single- and double-labeled neurons. Results show that virtually all neurons of the MTN (>97.5%), together with neurons in the visual tegmental relay zone immediately surrounding the MTNd, are single-labeled in all paired injections involving the NOT and the other target nuclei. It was found that about 69% of MTN neurons project exclusively to the NOT, 5–10% project to each one of the other nuclei, and 3% of MTN neurons project to more than one target. Based upon cell counts from the fluorescent material, and previous analysis of Nissl-stained serial sections, the findings show that virtually all MTN neurons are projection neurons. It was concluded that the MTN is comprised of independent projection systems, possibly involved in different aspects of generating optokinetic nystagmus.

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