Pierre A Sylvestre

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The mechanics of the eyeball and its surrounding tissues, which together form the oculomotor plant, have been shown to be the same for smooth pursuit and saccadic eye movements. Hence it was postulated that similar signals would be carried by motoneurons during slow and rapid eye movements. In the present study, we directly addressed this proposal by(More)
Although numerous investigations have probed the status of the vestibuloocular (VOR) during gaze shifts, its exact status remains strangely elusive. The goal of the present study was to precisely evaluate the dynamics of VOR suppression immediately before, throughout, and just after gaze shifts. A torque motor was used to apply rapid (100 degrees/s),(More)
Burst-tonic (BT) neurons in the prepositus hypoglossi and adjacent medial vestibular nuclei are important elements of the neural integrator for horizontal eye movements. While the metrics of their discharges have been studied during conjugate saccades (where the eyes rotate with similar dynamics), their role during disjunctive saccades (where the eyes(More)
Simple activities like picking up the morning newspaper or catching a ball require finely coordinated movements of multiple body segments. How our brain readily achieves such kinematically complex yet remarkably precise multijoint movements remains a fundamental and unresolved question in neuroscience. Many prevailing theoretical frameworks ensure(More)
Saccades made between targets at optical infinity require both eyes to rotate by the same angle. Nevertheless, these saccades are consistently accompanied by transient vergence eye movements. Here we have investigated whether the dynamics of these vergence movements depend on the trajectory of the coincident conjugate movement, and whether moving the head(More)
Burst neurons (BNs) in the paramedian pontine reticular formation provide the primary input to the extraocular motoneurons (MNs) during head-restrained saccades and combined eye-head gaze shifts. Prior studies have shown that BNs carry eye movement-related signals during saccades and carry head as well as eye movement-related signals during gaze shifts.(More)
When we look between objects located at different depths the horizontal movement of each eye is different from that of the other, yet temporally synchronized. Traditionally, a vergence-specific neuronal subsystem, independent from other oculomotor subsystems, has been thought to generate all eye movements in depth. However, recent studies have challenged(More)
Microstimulation experiments in the superior colliculus1 and single-unit recordings from its target, the premotor saccadic burst neurons2 (SBNs, located in the paramedian pontine reticular formation), have shown that the saccadic burst generator encodes head as well as eye movements during head-unrestrained gaze shifts. There is also evidence suggesting(More)
In this report, we provide the first characterization of abducens nucleus neuron (ABN) discharge dynamics during horizontal disjunctive saccades. These movements function to rapidly transfer the visual axes between targets located at different eccentricities and depths. Our primary objective was to determine whether the signals carried by ABNs during these(More)
The vestibular sensory apparatus and associated vestibular nuclei are generally thought to encode angular head velocity during our daily activities. However, in addition to direct inputs from vestibular afferents, the vestibular nuclei receive substantial projections from cortical, cerebellar, and other brainstem structures. Given this diversity of inputs,(More)
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