Behavioral and electrophysiological study of cutaneous trigeminal nerves in axolotls. II. the effects of cross-anastomosis of nerves
Griersmith, B.T.; Mark, R.F.
Brain Research 254(2): 287-301
ISSN/ISBN: 0006-8993 PMID: 7272781 DOI: 10.1016/0165-3806(81)90038-9
In two groups of axolotls, divisions of the trigeminal (Vth) nerve innervating the skin of the head were surgically crossed. The mandibular division innervating the ventral skin was cut and deflected dorsally towards the peripheral stumps of either the deep ophthalmic or the combined superficial ophthalmic and the maxillary divisions. The central cut end of the deep ophthalmic or the combined superficial ophthalmic and maxillary divisions was deflected ventrally towards the peripheral stump of the mandibular division. Behavioral responses from light tactile stimulation of the denervated skin reappeared after some months. They were a mixture of responses, some characteristic of the skin stimulated together with responses characteristic of skin that was normally supplied by the deflected nerve. Cutaneous receptive fields of all divisions were mapped electrophysiologically. The redirected mandibular had innervated either the area below the eye vacated by the maxillary or that medial to the eye formerly innervated by the deep ophthalmic, according to the type of operation. With varying degrees of success the dorsal nerves had innervated the ventral skin. The normal response from the ventral mandibular territory was never evoked by stimulation of the dorsal surface of the head, known to be innervated by the mandibular nerve. Ventral skin, proven electrophysiologically to be innervated by dorsal divisions, gave some responses characteristic of dorsal skin and some peculiar to the ventral skin.