Interstimulus interval effects on habituation of flexor withdrawal activity mediated by the functionally transected human spinal cord
Fuhrer, M.J.
Archives of Physical Medicine and Rehabilitation 57(12): 577-582
1976
ISSN/ISBN: 0003-9993 PMID: 999483 Document Number: 105937
The habituation of flexor withdrawal activity mediated by the functionally transected human spinal cord was investigated as a function of a wide range of different temporal intervals among the repetitive cutaneous stimuli. Nine patients with a chronic, transverse lesion of the cervical spinal cord were submitted to four daily habituation training series involving interstimulus intervals of either 1, 5, 25, or 125 seconds. The stimulus consisted of a 40-msec pulse train applied through surface electrodes to a midplantar site, and the response was expressed in terms of the goniometrically recorded dorsiflexion of the ankle. A reliable degree of habituation was found for the series involving the 1- and 5-second intervals. However, holding constant the number of stimuli involved in the comparisons, no habituation was found for the series involving intervals of 25 and 125 seconds.