The preganglionic sympathetic nerves, like other peripheral nerves, are endowed with a capacity for regeneration. The work of Langley,1 Tsukaguchi,2 Lee3 and others has shown that a lesion—even a large defect—in such nerves is quickly repaired by new growth of axis cylinders. Furthermore, the speed of regeneration compares favorably with that of somatic motor nerve fibers. In most of this work the cervical sympathetic cord and the ocular functions that it serves were utilized. For the sympathetic innervation of other regions, functional tests yielding satisfactory quantitative data were not available. However, the recent development of methods for measuring the electrical resistance of the skin and especially for following the negative variations in the electrical potential of the skin, of central origin, the spontaneous waves and the "galvanic skin response," now allows accurate study of sympathetic function in relatively hairless surfaces of the skin.
Skin-resistance, as the term
TOWER SS, RICHTER CP. INJURY AND REPAIR WITHIN THE SYMPATHETIC NERVOUS SYSTEMI. THE PREGANGLIONIC NEURONS. Arch NeurPsych. 1931;26(3):485-495. doi:10.1001/archneurpsyc.1931.02230090018002