Structure of the primate oculomotor burst generator. I. Medium-lead burst neurons with upward on-directions.

摘要: 1. To investigate the structure of primate burst generator for vertical saccades, we obtained intra-axonal records from medium-lead neurons with upward on-directions (UMLBs) in alert, behaving squirrel monkeys, while monitoring their spontaneous eye movements. After physiological characterization, these UMLBs were injected horseradish peroxidase. 2. (n = 14) had no activity and emitted bursts action potentials that preceded rapid movements by approximately 6 ms. Parameters (duration number spikes) highly correlated parameters movement amplitude displacement eyes). 3. The axons six projected to oculomotor complex. Their somata (4 recovered) all rostral interstitial nucleus medial longitudinal fasciculus (riMLF). traveled caudally (MLF) ramified Cajal (NIC) before entering nucleus. Five terminated bilaterally subdivisions innervating superior rectus inferior oblique muscles therefore presumed be excitatory. One axon ipsilateral complex was inhibitory. 4. Additionally, our data demonstrate posterior commissure (nPC) may also contain UMLBs. one such neuron crossed midline within provided terminal fields contralateral nPC, riMLF, NIC, mesencephalic reticular formation but not 5. In conclusion, mesencephalon monkey contains have both connections are necessary either provide motoneurons extraocular eyes pulse they display during saccades or inhibit antagonists. Furthermore, some better suited closing feedback path local loop rather than providing direct input motoneurons.