Longitudinal distribution of negative cord dorsum potentials following stimulation of afferent fibres in the left inferior cardiac nerve.
Cord dorsum potentials were recorded along the spinal cord following electrical stimulation of afferent fibres of the left inferior cardiac nerve in chloralose anaesthetized cats. The potentials were more pronounced in spinal than in intact cats. Afferent fibres which generated cord dorsum potentials in the cervical spinal cord were localized mainly in T2 and T3 and to a smaller extent in C8 and T1 dorsal roots. The responses consisted of two waves: with short (7.0 ms; N3 wave) and long (56 ms; N4 wave) latency to the onset of potentials. N3 and N4 waves were generated by group III and group IV afferent fibres, respectively. The N3 wave was maximal at C8 and T1 spinal cord level and could be detected at least 5-6 segments rostrally from the level of afferent input responsible for its generation. The N4 wave could be detected at least 4 segments rostrally from its afferent fibre input. We conclude that afferent fibres from the left inferior cardiac nerve activate neurones in the cervical spinal cord. The implications of such finding are discussed.
D000818:Animals; D002415:Cats; D003655:Decerebrate State; D004558:Electric Stimulation; D005071:Evoked Potentials; D006321:Heart / Q000294:innervation*; D009475:Neurons, Afferent / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*