Terminal Distribution of Spinoreticular Fibers in the Cat

The studies of the spinoreticular fibers found in the literature indicate that long ascending fibers, passing beyond the mesencephalon, take origin particularly from certain regions of the brain stem reticular formation.

Abstract

Fibers ascending in the spinal cord and terminating in the reticular formation of the brain stem were demonstrated around the turn of the century in experimental animals,22,23,30,31,40as well as in man.15,37After the discovery of the ascending reticular activating system by Moruzzi and Magoun,29renewed attention was directed to the pathways mediating spinal impulses to the reticular formation, and recent experimental anatomical investigations6,20,21, 26-28have confirmed and extended the findings made in studies with the Marchi method by the classical workers. In a previous study12we have shown that long ascending fibers, passing beyond the mesencephalon, take origin particularly from certain regions of the brain stem reticular formation. From a functional point of view it would be of interest to know whether these regions receive the majority of the spinoreticular fibers. The studies of the spinoreticular fibers found in the literature indicate that this