| | 1 | Author
| H. Endrick, E. A. Eckert, K. Urt, H. Am Dorf | Requires cookie* | | | Title
| Action Potentials in "Non-Spiking" Visual Interneurones  | | | | Abstract
| The response o f the homolateral "horizontal cells" (H-cells) o f the third visual neuropile o f the blowfly, Phoenicia sericata, has been investigated by intracellular recordings coupled with dye injections (Procion Yellow, cobaltous chloride). Responses were obtained from their terminal axon endings in the central protocerebrum. Under natural conditions, the horizontal cells respond not with graded potentials as reported previously, but with action potentials upon stimulation by regressive pattern motion within the contralateral receptive field. The stimulus-induced responses change from action potentials to graded signals within a few minutes after opening the head capsule. The possible causes o f this change, namely hypoxic conditions and a consequent depletion of the ATP-supply, are consistent with the experimental data: a change in the resting potential as well a reduction o f the spike amplitude. Furthermore, the possibility of two functionally different output regions o f the H-cells is discussed, namely, (1) the terminal axon endings appear to conduct action potentials induced by the contralateral input (to the H-cells). Thus, these endings provide a solely contralateral, i.e. "monocular output". Whereas (2) the axonal arborisation appears to conduct graded signals elicited by the ipsilateral input onto which the contralateral input is superimposed, thus providing a "binocular output". | | | |
Reference
| Z. Naturforsch. 36c, 470—4 (1981); received August 7 1980/January 21 1981 | | | |
Published
| 1981 | | | |
Keywords
| Vision, Diptera, Central Nervous System, Identified Neurones, Graded Signal Transmission | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0470.pdf | | | | Identifier
| ZNC-1981-36c-0470 | | | | Volume
| 36 | |
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