The anatomy of the nervous system, from the standpoint of development and function . and especially with those re-actions necessary to maintain or to re-establish that evenly balanced spacialorientation known as equilibrium. The cerebello-rubro-spinal path is the con-duction system primarily concerned in these reactions. What is perhaps the first direct experimental evidence of the function of thissystem has been given by Weed (1914). The extensor rigidity, so characteristic EFFERENT IA HIS AND I-I I I I \ arcs 327 of decerebrated dogs, which Sherrington (1906) clearly showed to be a proprioce
The anatomy of the nervous system, from the standpoint of development and function . and especially with those re-actions necessary to maintain or to re-establish that evenly balanced spacialorientation known as equilibrium. The cerebello-rubro-spinal path is the con-duction system primarily concerned in these reactions. What is perhaps the first direct experimental evidence of the function of thissystem has been given by Weed (1914). The extensor rigidity, so characteristic EFFERENT IA HIS AND I-I I I I \ arcs 327 of decerebrated dogs, which Sherrington (1906) clearly showed to be a proprioceptive reflex that under normal conditions serves to keep the limbs From bending under the weight of the body, is apparently dependent upon the integrity ofthe cerebello-rubro-spinal path. Weed showed that removal of the cerebellum,section of the superior cerebellar peduncles, or transection of the mesencephalonbelow the level of the red nucleus obliterated or greatly decreased this rigidity. From frontal lobe and corpui striatumThalamus Rubrospinal tract ^Rubroreticular tract Red nucleusBrachium < onjunciivum Dentate nucleus Pons Rubrospinal trad Medulla oblongata Reticulospinal tract Spinal cord Fig. 243.—Diagram showing the connections of the red nucleus: A, Ventral tegmentaldecussation; B, decussation of the brachium conjunctivum; C and D, descending fibers from bra-chium conjunctivum, before and after its decussation respectively. On the other hand, stimulation of the area occupied by the red nucleus on thecut surface of the mesencephalon in decerebrated dogs increased the rigidity. IMPORTANT REFLEX ARCS We have considered the afferent paths leading to the cerebral cortex and tothe cerebellum as well as the efferent channels which conduct impulses from thesecenters to the skeletal musculature. But there are many more direct pathsby which impulses may travel from receptor to effector, and these are known asreflex arcs. It will be worth while to review briefly a few
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectnervoussystem, bookye
