The distribution of afferent fibers from the gastrocnemius-soleus muscle in the dorsal horn of the cat, as revealed by the transport of horseradish peroxidase.

The transganglionic transport of horseradish peroxidase (HRP) was used to examine the distribution of afferent fibers from the gastrocnemius-soleus (GS) muscle in the dorsal horn of the cat. Intense labeling was consistently observed in lamina I (in segments L4 to S3) and in the lateral portion of lamina V (segments L6 and S1-3), but not to any significant extent in laminae II-IV. These terminal fields were ascribed to the small-diameter (group III/IV) GS afferent fibers.