Neural integration in ocular motility.
The NI is an important part of the ocular motor system; one that determines both normal and certain pathological eye movements. As this chapter has chronicled, bioengineers have played the major role in developing this concept. Early models predicted its use by the ocular motor system for accuracy and stability. Required velocity-to-position signal conversions (i.e., mathematical integration) necessitated its existence in the brain stem. Each type of conjugate eye movement used integration to convert premotor velocity commands into the required position commands. Successful synergistic operation of all subsystems was best served by one common NI but the flexibility and observed independence of certain functions suggested a local NI for the PG. The very nature of integration resulted in the realization that one neuron could not perform this mathematical operation and therefore, the NI was likely to be distributed in several brain stem locations. Finally, the creation of neural network models that accomplish the task of mathematical integration demonstrated the need for reciprocal inhibition. Although the theoretical grounds for some of the hypotheses of bioengineers were not always based in neurophysiology, many of the resulting conclusions are supported by later neurophysiological evidence.
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D001933:Brain Stem / Q000502:physiology; D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D009046:Motor Neurons / Q000502:physiology; D009801:Oculomotor Muscles / Q000294:innervation*; D011698:Pursuit, Smooth / Q000502:physiology; D012438:Saccades / Q000502:physiology