Optic inputs to identified neck-muscle motoneurons of Salamandra salamandra (L.): an intracellular recording study.
By means of retrograde horseradish peroxidase (HRP) transport, motoneurons innervating the musculus intertransversarius capitis superior (m.i.c.s.) of Salamandra salamandra (L.) were labeled from the level of the vagus nerve to the fourth spinal nerve. The bulk of the neurons was situated between the first and the third spinal nerve. The HRP-labelings revealed smaller cells with one apical dendrite and large cells with two main dendrites originating from opposite poles of the soma. With intracellular recordings from m.i.c.s. motoneurons a bimodal distribution of the antidromic latencies was found after intramuscular electrical stimulations. Optic inputs to the motoneurons were examined with electrical stimulation of the optic discs. It was shown that the majority of optic signals to the motoneurons originate from the contralateral eye. The latency distribution of these inputs suggests that most of the signals reach the motoneurons via indirect pathways involving at least one additional synapse. However, a few motoneurons seemed to be directly coupled with visual centers.
Institut für Zoologie, Technische Hochschule Darmstadt, Fed. Rep. Germany.
G
G
Manteuffel
C
C
Naujoks-Manteuffel
D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D007425:Intracellular Membranes / Q000502:physiology; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology*; D009132:Muscles / Q000294:innervation*; D009334:Neck Muscles / Q000294:innervation*; D009475:Neurons, Afferent / Q000502:physiology; D009799:Ocular Physiological Phenomena; D014562:Caudata / Q000502:physiology*; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology