Abstract
Spontaneous, subthreshold fluctuations of membrane potential are recorded in the eccentric cell body or dendrite of the dark-adapted Limulus ommatidium. These slow potential fluctuations (SPF's) are random in amplitude and in time of occurrence. The relation between average frequency of SPF's and light intensity is linear for low light intensities and becomes a non-linear saturation for higher intensities. The occurrences of SPF's have Poisson statistics in the dark but are non-Poisson with light stimuli. Light-adapting the ommatidium greatly decreases the SPF amplitude, and it increases the average frequency of SPF's in the dark and in response to light (facilitatory action). The shape (time course of response) of the SPF does not change at different light intensities and it is the result of a concurrent and conterminous change in membrane resistance. The functional properties of the SPF's are analyzed in terms of a stochastic model based on the summation of random events in time ("shot effect").
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Selected References
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- BOYD I. A., MARTIN A. R. Spontaneous subthreshold activity at mammalian neural muscular junctions. J Physiol. 1956 Apr 27;132(1):61–73. doi: 10.1113/jphysiol.1956.sp005502. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BROCK L. G., COOMBS J. S., ECCLES J. C. The recording of potentials from motoneurones with an intracellular electrode. J Physiol. 1952 Aug;117(4):431–460. doi: 10.1113/jphysiol.1952.sp004759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DEL CASTILLO J., KATZ B. Biophysical aspects of neuro-muscular transmission. Prog Biophys Biophys Chem. 1956;6:121–170. [PubMed] [Google Scholar]
- DEL CASTILLO J., KATZ B. Statistical factors involved in neuromuscular facilitation and depression. J Physiol. 1954 Jun 28;124(3):574–585. doi: 10.1113/jphysiol.1954.sp005130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DUDEL J., KUFFLER S. W. The quantal nature of transmission and spontaneous miniature potentials at the crayfish neuromuscular junction. J Physiol. 1961 Mar;155:514–529. doi: 10.1113/jphysiol.1961.sp006644. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FATT P., KATZ B. Spontaneous subthreshold activity at motor nerve endings. J Physiol. 1952 May;117(1):109–128. [PMC free article] [PubMed] [Google Scholar]
- FRANKENHAEUSER B. Steady state inactivation of sodium permeability in myelinated nerve fibres of Xenopus laevis. J Physiol. 1959 Oct;148:671–676. doi: 10.1113/jphysiol.1959.sp006316. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FUORTES M. G. Electric activity of cells in the eye of Limulus. Am J Ophthalmol. 1958 Nov;46(5 Pt 2):210–223. doi: 10.1016/0002-9394(58)90800-6. [DOI] [PubMed] [Google Scholar]
- FUORTES M. G., POGGIO G. F. Transient responses to sudden illumination in cells of the eye of Limulus. J Gen Physiol. 1963 Jan;46:435–452. doi: 10.1085/jgp.46.3.435. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FUORTES M. G., YEANDLE S. PROBABILITY OF OCCURRENCE OF DISCRETE POTENTIAL WAVES IN THE EYE OF LIMULUS. J Gen Physiol. 1964 Jan;47:443–463. doi: 10.1085/jgp.47.3.443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GRANIT R., PHILLIPS C. G. Excitatory and inhibitory processes acting upon individual Purkinje cells of the cerebellum in cats. J Physiol. 1956 Sep 27;133(3):520–547. doi: 10.1113/jphysiol.1956.sp005606. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KUSANO K., HAGIWARA S. On the integrative synaptic potentials of Onchidium nerve cell. Jpn J Physiol. 1961 Feb 15;11:96–101. doi: 10.2170/jjphysiol.11.96. [DOI] [PubMed] [Google Scholar]
- LILEY A. W. An investigation of spontaneous activity at the neuromuscular junction of the rat. J Physiol. 1956 Jun 28;132(3):650–666. doi: 10.1113/jphysiol.1956.sp005555. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MILLER W. H. Morphology of the ommatidia of the compound eye of Limulus. J Biophys Biochem Cytol. 1957 May 25;3(3):421–428. doi: 10.1083/jcb.3.3.421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- NISHI S., KOKETSU K. Electrical properties and activities of single sympathetic neurons in frogs. J Cell Comp Physiol. 1960 Feb;55:15–30. doi: 10.1002/jcp.1030550104. [DOI] [PubMed] [Google Scholar]
- SCHOLES J. H. DISCRETE SUBTHRESHOLD POTENTIALS FROM THE DIMLY LIT INSECT EYE. Nature. 1964 May 9;202:572–573. doi: 10.1038/202572a0. [DOI] [PubMed] [Google Scholar]
- TAUC L. Analyses unitaires d'activités synaptiques chez l'Aplysie, révélant la mise en jeu de neurones intermédiaires dans le ganglion abdominal. J Physiol (Paris) 1958 Mar;50(2):541–544. [PubMed] [Google Scholar]
