Abstract
The ncural integrator has been at least a conceptual portion of the vestibular system since the earliest vestibular studies. Like others before him, Robinson (e.g. 1975) observed adequate stimulation of the vestibular end organ by angular acceleration results in eye position as the final output of the vestibular-ocular reflex (VOR). Therefore, he reasoned that there must be two levels of integration, one attributable to the mechanics of the cupula and the other to an hypothesized neural integrator. He further suggested that this integrator is common for all subsystems of conjugate eye movement.The results of both single-unit recordings and lesions suggest that the interstitial nucleus of Cajal (INC) and the nucleus prepositus hypoglossi (NPH) of both cats and monkeys are part of the vertical and horizontal oculomotor integrators, respectively. Both structures contain neurons that have discharge components related to velocity and position, as might be expected of a neural integrator. In addition, injury to either structure weakens integrator function. The clearest effect of lesions is on gaze-holding ability. Damage to either the NPH or the INC impairs an animal's ability to maintain eccentric gaze. The INC alone cannot perform the integrating function. Strong reciprocal connections between the INC and the vestibular nuclei play an important role in vertical integration. In addition, the cerebellar flocculus may also be included in the integrator. Some of the oculomotor subsystems may have separate integrators.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
