Do brainstem omnipause neurons terminate saccades?

Rucker, Janet C.; Ying, Sarah H.; Moore, Willa; Optican, Lance M.; Büttner‐Ennever, Jean A.; Keller, Edward L.; Shapiro, Barbara E.; Leigh, R. John

doi:10.1111/j.1749-6632.2011.06170.x

Cited by 24 publications

(20 citation statements)

References 48 publications

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“…We observed the same variation of saccadic PV in the phase plane plots of eye position vs. velocity as seen in a previous study ( 4 ). This is due to the malfunction of omnipause neurons in the pontine nucleus raphe interpositus that control saccade generation by inhibiting the activity of burst neurons ( 26 ).…”

Section: Discussionmentioning

confidence: 99%

Oculomotor and Vestibular Findings in Gaucher Disease Type 3 and Their Correlation with Neurological Findings

et al. 2018

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Objectives: To evaluate the function of the oculomotor and vestibular systems and to correlate these findings with the clinical status of patients with Gaucher disease type 3 (GD3). The goal of this cross-sectional and longitudinal study was to find oculomotor biomarkers for future clinical trials.Methods: Twenty-six patients with GD3 were assessed for eligibility and 21 were able to perform at least one task. Horizontal and vertical reflexive saccades, smooth pursuit, gaze-holding, optokinetic nystagmus, and horizontal vestibulo-ocular reflex (VOR) were examined by video-oculography/video-head impulse test and compared concurrently with 33 healthy controls. The Scale for the Assessment and Rating of Ataxia (SARA), the modified Severity Scoring Tool (mSST), and Grooved Pegboard Test (GPT) were administered to assess overall neurological function. Eleven patients were also re-assessed after 1 year.results: Nine out of 17 patients exhibited gaze-holding deficits. One patient had upbeat nystagmus. Three patients presented with bilateral abducens palsy in combination with central oculomotor disorders, suggesting a bilateral involvement of the abducens nucleus. Horizontal angular VOR gain was reduced in all patients (0.66 ± 0.37) compared with controls (1.1 ± 0.11, p < 0.001). Most strongly correlated with clinical rating scales were peak velocity of downward saccades (SARA: ρ = −0.752, p < 0.0005; mSST: ρ = −0.611, p = 0.003; GPT: ρ = −0.649, p = 0.005) and duration of vertical saccades interpretation: This study shows neuronal degeneration of the brainstem and cerebellum with combined involvement of both supranuclear and nuclear oculomotor structures and the vestibular system in GD3. We also identified oculomotor parameters that correlate with the neurological status and can be used as biomarkers in future clinical trials.

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Section: Discussionmentioning

confidence: 99%

Oculomotor and Vestibular Findings in Gaucher Disease Type 3 and Their Correlation with Neurological Findings

et al. 2018

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“…Still, mechanisms other than OPN discharge may contribute to saccadic termination. The oculomotor cerebellum has been also implicated in the termination of rapid gaze displacements (Fuchs et al 2010 ; Rucker et al 2011 ). We suggest a straightforward, mechanistic explanation of our findings, i.e.…”

Section: Discussionmentioning

confidence: 99%

Fast gaze reorientations by combined movements of the eye, head, trunk and lower extremities

et al. 2015

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Large reorientations of the line of sight, involving combined rotations of the eyes, head, trunk and lower extremities, are executed either as fast single-step or as slow multiple-step gaze transfers. In order to obtain more insight into the mechanisms of gaze and multisegmental movement control, we have investigated time-optimal gaze shifts (i.e. with the instruction to move as fast as possible) during voluntary whole-body rotations to remembered targets up to 180° eccentricity performed by standing healthy humans in darkness. Fast, accurate, single-step movement patterns occurred in approximately 70 % of trials, i.e. considerably more frequently than in previous studies with the instruction to turn at freely chosen speed (30 %). Head-in-space velocity in these cases was significantly higher than during multiple-step transfers and displayed a conspicuously regular bell-shaped profile, increasing smoothly to a peak and then decreasing slowly until realignment with the target. Head-in-space acceleration was on average not different during reorientations to the different target eccentricities. In contrast, head-in-space velocity increased with target eccentricity due to the longer duration of the acceleration phase implemented during trials to more distant targets. Eye saccade amplitude approached the eye-in-orbit mechanical limit and was unrelated to eye/head velocity, duration or target eccentricity. Overall, the combined movement was stereotyped such that the first two principal components accounted for data variance almost up to gaze shift end, suggesting that the three mechanical degrees of freedom under consideration (eye-in-orbit, head-on-trunk and trunk-in-space) are on average reduced to two kinematic degrees of freedom (i.e. eye, head-in-space). Synchronous EMG activity in the anterior tibial and gastrocnemius muscles preceded the onset of eye rotation. Since the magnitude and timing of peak head-in-space velocity were scaled with target eccentricity and because head-on-trunk and trunk-in-space displacements were on average linearly correlated, we propose a separate controller for head-in-space movement, whereas the movement of the eye-in-space may be, in contrast, governed by global, i.e. gaze feedback. The rapid progression of the line of sight can be sustained, and the reactivation of the vestibulo-ocular reflex would be postponed, until gaze error approaches zero only in association with a strong head-in-space neural control signal.

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“…Although not uniformly found,20,21 the prevailing pathological finding in ET brains has been reduced numbers of PCs, along with increased PC axonal swellings (“torpedoes”) 22–24. Furthermore, in late onset Tay–Sachs (LOTS), in which PCs in the vermis appear to be largely destroyed,25 saccades are similarly characterized by transient slowing of saccadic velocities,26,27 albeit more profoundly than ET cases. Moreover, findings of transient slowing of saccades in ET and LOTS are consistent with current theories suggesting that normally precisely timed inhibitory signals from PCs in the vermis “choke off” saccadic drive signals originating from the superior colliculus 28,29…”

Section: Discussionmentioning

confidence: 99%