Organization of Ascending Spinal Tracts Activated from Forelimb Afferents in the Cat

Iolmqvist, B., O. Oscarsson and N. Uddenberg. Organization of ascending spinal tracts activated from forelimb afferents in the cat. Acta physiol. scand. 1963. 58. 68—76. — Discharges evoked in coarsefibred ascending spinal tracts on stimulation of muscle and skin nerves in the forelimbs were recorded from dissected fascicles of the cord at C3. The general organization of tracts activated from fore‐limb afferents is similar to that of tracts activated from hindlimb afferents: uncrossed tracts are located in the dorsal part of the lateral funiculus and crossed tracts ventrally thereof. In the cervical region the uncrossed tracts activated from forelimb afferents occupy a larger area than those activated from hindlimb afferents. — Group I muscle afferents activate only one ascending tract. It is uncrossed and ascends in the middle third of the lateral funiculus. This tract is not identical with either the dorsal or the ventral spinocerebellar tract. It is suggested that these two tracts lack“forelimb components”. — The dorsomedial tract activated from low threshold cutaneous afferents and terminating in the lateral cervical nucleus seems to originate from both hindlimb and forelimb levels of the cord.