ORTHODROMICALLY PRODUCED CHANGES IN MOTONEURONAL EXTRACELLULAR FIELDS

Abstract

Primarily negative extracellular spike potentials of single spinal motoneurons of cats have been examined in the presence and in the absence of orthodromic conditioning input to the cells. Usually the orthodromic conditioning produces little or no change in the antidromic spike. Change in both the initial negative spike component and the final positive component were seen, however. Increased synchrony of activation of A and B spike generators produced occlusion of the currents generated by them. Increased spike negativity and alteration in spike configuration were consistent with the hypothesis that orthodromic conditioning could produce an alteration in the spatial extent of the B generator.