Responses to electrical stimulation of denervated human muscle fibres recorded with single fibre EMG

Abstract

Denervated muscle fibres were stimulated electrically with needle electrodes introduced close to a recording single fibre electrode. The denervated muscle fibre could be driven with rates up to 100 Hz. The jitter was large at threshold but low at suprathreshold stimulus strength. There was evidence of discrete low threshold sites along the denervated muscle fibre, seen as stepwise latency change on smoothly changing stimulus strength, ephaptic activation from other fibres and also as extra-discharges originating from such sites.