Abstract
A statistical mathematical model of the discharge in a single optic nerve fiber is proposed, based on a discharge with intervals between impulses distributed independently according to a gamma distribution ("gamma discharge"). A light stimulus distorts the time axis of this discharge according to a "frequency function" which is characteristic of the stimulus. A linear filter is described which calculates the likelihood of a certain stimulus when the nerve fiber message is fed into it. This filter forms the basis of theoretical nerve message analyzers for three visual experiments: (a) The detection of the occurrence of a flash of light of known intensity and time of occurrence, (b) the detection of the time of occurrence of a flash of known intensity, and (c) The estimation of the intensity of a flash occurring at a known time. Possible neural mechanisms in the brain for analyzing optic nerve messages, based on the above mathematical models, are suggested. Changes of excitability or discharge frequency correspond to the output of the likelihood filter. Any such mechanism must be sufficiently plastic to have a response matched to each expected stimuus for most efficient vision near threshold.
Full Text
The Full Text of this article is available as a PDF (961.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BISHOP P. O., JEREMY D., MCLEOD J. G. Phenomenon of repetitive firing in lateral geniculate of cat. J Neurophysiol. 1953 Jul;16(4):437–447. doi: 10.1152/jn.1953.16.4.437. [DOI] [PubMed] [Google Scholar]
- FITZHUGH R. The statistical detection of threshold signals in the retina. J Gen Physiol. 1957 Jul 20;40(6):925–948. doi: 10.1085/jgp.40.6.925. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HARTLINE H. K., WAGNER H. G., MACNICHOL E. F., Jr The peripheral origin of nervous activity in the visual system. Cold Spring Harb Symp Quant Biol. 1952;17:125–141. doi: 10.1101/sqb.1952.017.01.013. [DOI] [PubMed] [Google Scholar]
- KUFFLER S. W., FITZHUGH R., BARLOW H. B. Maintained activity in the cat's retina in light and darkness. J Gen Physiol. 1957 May 20;40(5):683–702. doi: 10.1085/jgp.40.5.683. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARSHALL W. H. Excitability cycle and interaction in geniculate-striate system of cat. J Neurophysiol. 1949 Jul;12(4):277–288. doi: 10.1152/jn.1949.12.4.277. [DOI] [PubMed] [Google Scholar]