HEAD AND RIDDOCH,1 in their classic experiments on patients with gross spinal cord injuries, found facilitation of spinal reflexes in that part of the cord below the level of the lesion and without suprasegmental control. It was shown that a sufficient stimulus to any receptive surface whose afferent fibers entered the distal stump of the cord was liable to evoke a massive response which overflowed widely into regions of the spinal cord normally associated with other reflexes (assuming that recovery from spinal cord "shock" and resumption of reflex activity of the distal stump of the spinal cord was not prevented by such complications as general infection and toxemia).
Especially investigated were abnormal autonomic reflex effects due to afferent impulses from bladder and bowel distention, both those of spontaneous occurrence due to urinary obstruction or flatulence and those artificially induced by inflation of the bladder or enemas. Outbursts of intense
SCHUMACHER GA, GUTHRIE TC. STUDIES ON HEADACHEMechanism of Headache and Observations on Other Effects Induced by Distention of Bladder and Rectum in Subjects with Spinal Cord Injuries. AMA Arch NeurPsych. 1951;65(5):568-580. doi:10.1001/archneurpsyc.1951.02320050025003