Properties of spinal cord processing of femoral venous afferent input revealed by analysis of evoked potentials.

Two characteristics of spinal cord interneurons which receive inputs from femoral-saphenous venous afferents were examined. The shortest pathway between primary femoral-saphenous venous afferents and alpha-motoneurons was shown to be a di- or tri-synaptic circuit. In addition, the largest focal synaptic field potentials elicited by venous afferent stimulation at short latency were recorded from Rexed's lamina V. It was thus concluded that most of the first interneurons excited by venous afferents are found in this lamina.