The saccadic system and the vestibulo-ocular reflex in the cat do not share the same integrator

Godaux, Emile; Laune, Jean-Marc

doi:10.1016/0304-3940(83)90379-8

Cited by 11 publications

(4 citation statements)

References 10 publications

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“…Furthermore, Godaux and Cheron (1996) have reported that in alert cats the eye position sensitivity of PH neurons during intersaccadic fixation was equal to that measured during VOR. However, some pharmacological results suggest that at least some of the subsystems may have separate integrators (Godaux and Laune, 1983;Pastor et al, 1994;Yokota et al, 1994). In our experiments, the use of NO donors, as well as 8-Br-cGM P, revealed an alteration of the integrator for spontaneous eye movements, whereas the VOR gain or phase did not change, indicating that the integrator for VOR remained intact.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Action and Targets of Nitric Oxide in the Oculomotor System

1998

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Nitric oxide (NO) production by neurons in the prepositus hypoglossi (PH) nucleus is necessary for the normal performance of eye movements in alert animals. In this study, the mechanism(s) of action of NO in the oculomotor system has been investigated. Spontaneous and vestibularly induced eye movements were recorded in alert cats before and after microinjections in the PH nucleus of drugs affecting the NO-cGMP pathway. The cellular sources and targets of NO were also studied by immunohistochemical detection of neuronal NO synthase (NOS) and NO-sensitive guanylyl cyclase, respectively. Injections of NOS inhibitors produced alterations of eye velocity, but not of eye position, for both spontaneous and vestibularly induced eye movements, suggesting that NO produced by PH neurons is involved in the processing of velocity signals but not in the eye position generation. The effect of neuronal NO is probably exerted on a rich cGMP-producing neuropil dorsal to the nitrergic somas in the PH nucleus. On the other hand, local injections of NO donors or 8-Br-cGMP produced alterations of eye velocity during both spontaneous eye movements and vestibulo-ocular reflex (VOR), as well as changes in eye position generation exclusively during spontaneous eye movements. The target of this additional effect of exogenous NO is probably a well defined group of NO-sensitive cGMP-producing neurons located between the PH and the medial vestibular nuclei. These cells could be involved in the generation of eye position signals during spontaneous eye movements but not during the VOR.

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Section: Discussionmentioning

confidence: 99%

Mechanisms of Action and Targets of Nitric Oxide in the Oculomotor System

1998

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“…Neuroleptics were recently described to affect differently the saccadic and the vestibular integrator (Godaux & Laune, 1983). The present lesions of the m.v.n.…”

Section: Correlation With the Neuroanatomical Connexionsmentioning

confidence: 99%

“…and the saccadic system share a final common integrator (Robinson, 1975(Robinson, , 1981 although some doubt subsists (see Godaux & Laune, 1983). Nevertheless, several nuclei are candidates for the integrators) underlying structuress.…”

Section: Introductionmentioning

confidence: 99%

Lesions in the cat prepositus complex: effects on the vestibulo‐ocular reflex and saccades.

Chéron¹,

Godaux²,

Laune³

et al. 1986

The Journal of Physiology

132

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SUMMARY1. The effects of bilateral electrolytic lesions within and around the prepositus hypoglossi (p.h.) nucleus on horizontal saccades in the dark and on the horizontal sinusoidal vestibulo-ocular reflex (v.o.r.) in the dark were studied.2. After p.h. lesion, including its rostral part between P 7 and P 8, the v.o.r. showed a phase lead as much as about 90 deg at 0-10 Hz. A significant gain reduction paralleled that phase lead at lower frequencies. A large post-saccadic drift was also observed, the time constant of which ranged from 0 3 to 0-6 s.3. After p.h. lesion extending from P 8 to P 11 (but sparing the rostral part of the p.h.), no significant gain or phase lead change was observed. Post-saccadic drift was either missing or weak.4. A bilateral medial vestibular nucleus (m.v.n.) lesion from P 7 to P 11 produced a marked gain decrease, paralleled by a marked phase advance. A post-saccadic drift was observed (r = 0-6 s).5. A surgical mid-line lesion from P 7 to P 11 (depth: about 2 mm) was followed by no remarkable change in the gain and in the phase of the v.o.r. No post-saccadic drift was observed after such lesion.6. It was concluded that (i) both the horizontal v.o.r. integration processing, and the horizontal saccadic integration processing were destroyed when an electrolytic lesion was made 'in the region of' the rostral part of the p.h. nucleus, and that (ii) the posterior four-fifths of the p.h. was the location of neither the horizontal v.o.r. integrator nor the horizontal saccadic integrator.

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“…(Keller, 1974); it should also supply a position signal from the velocity signal originating from either the semicircular canals (Skavenski & Robinson, 1973) or the retina (Cohen, Matsuo & Raphan, 1977). All three integration processings should be done by a common final integrator (Robinson, 1975(Robinson, , 1981, although some doubt subsists (Godaux & Laune, 1983).…”

Section: Introductionmentioning

confidence: 99%

Disabling of the oculomotor neural integrator by kainic acid injections in the prepositus‐vestibular complex of the cat.

Chéron

Godaux

1987

The Journal of Physiology

135

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SUMMARY1. This study was intended to test the candidature of the prepositus-vestibular nuclear complex for being the location of the oculomotor neural integrator (Robinson's integrator).2. Microinjections of kainic acid (2 jug dissolved in 1 1ul) were made in awake cats. Injection sites were located either in the prepositus hypoglossi nucleus (p.h.), the medial vestibular nucleus (m.v.n.), the medial longitudinal fasciculus (m.l.f.) or in the magnocellular tegmental field of the reticular formation.3. Theory predicts that a complete disabling of the neural integrator will cause (a) an exponential post-saccadic drift whose time constant will be 0-16 s in the dark (b) a phase lead of + 93 deg as the vestibulo-ocular reflex is tested at 0-10

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The saccadic system and the vestibulo-ocular reflex in the cat do not share the same integrator

Cited by 11 publications

References 10 publications

Mechanisms of Action and Targets of Nitric Oxide in the Oculomotor System

Mechanisms of Action and Targets of Nitric Oxide in the Oculomotor System

Lesions in the cat prepositus complex: effects on the vestibulo‐ocular reflex and saccades.

Disabling of the oculomotor neural integrator by kainic acid injections in the prepositus‐vestibular complex of the cat.

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