Spinal neurons with branched axons traveling in both the dorsal and dorsolateral funiculi.

Antidromic search stimuli were delivered to cervical (C2-C3) dorsal and dorsolateral funiculi that were dissected apart from one another and from the rest of the spinal cord. Fifty-six neurons were antidromically identified in the dorsal horn of the lumbosacral enlargement. Of these neurons, 23 were activated antidromically from both the dorsal columns and the ipsilateral dorsolateral funiculus. The neurons were found at depths corresponding to laminae III and IV. About half of the neurons responded only to innocuous, tactile stimuli whereas the other half responded to both innocuous and noxious stimuli. The existence of neurons with branched axons ascending both the dorsal and dorsolateral funiculi raises the possibility that the dorsal column postsynaptic and spinocervical tracts may not be completely independent projections.