Optic inputs to identified neck-muscle motoneurons of Salamandra salamandra (L.): an intracellular recording study

• Published in: Journal fur Hirnforschung Vol. 28; no. 6; p. 625
• Main Authors: Manteuffel, G, Naujoks-Manteuffel, C
• Format: Journal Article
• Language: English
• Published: Germany 1987
• Subjects: Animals; Electric Stimulation; Electrophysiology; Intracellular Membranes - physiology; Motor Neurons - cytology; Motor Neurons - physiology; Muscles - innervation; Neck Muscles - innervation; Neurons, Afferent - physiology; Ocular Physiological Phenomena; Urodela - physiology; Visual Pathways - cytology; Visual Pathways - physiology
• ISSN: 0021-8359

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.