Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-10T12:34:51.714Z Has data issue: false hasContentIssue false

The density recovery profile: A method for the analysis of points in the plane applicable to retinal studies

Published online by Cambridge University Press:  02 June 2009

R. W. Rodieck
Affiliation:
Department of Ophthalmology, The University of Washington, seattle

Abstract

The density recovery profile is a plot of the spatial density of a set of points as a function of the distance of each of those points from all the others. It is based upon a two-dimensional point autocorrelogram. If the points are randomly distributed, then the profile is flat, with a value equal to the mean spatial density. Thus, any deviation from this value indicates that the presence of the object represented by the point alters the probability of encountering nearby objects of the same set. Increased value near an object indicates clustering, decreased value near an object indicates anticlustering. The method appears to be unique in its ability to provide quantitative measures of the anticlustered state. Two examples are presented. The first is based upon a sample of the distribution of the somata of starburst amacrine cells in the macaque retina; the second is based upon the distribution of the terminal enlargements on the dendrites of a single macaque ganglion cell that projects to the superior colliculus. In both cases, the density recovery profile is initially lower than the mean density, and increases up to the plateau at the value of the mean density. Two useful measures can be derived from this profile: an intensive parameter termed the effective radius, which quantifies the extent of the region of decreased probability and is insensitive to random undersampling of the underlying distribution, and an extensive parameter termed the packing factor, which quantifies the degree of packing possible for a given effective radius, and is insensitive to scaling. An extension of this method, applicable to correlations between two superimposed distributions, and based upon a two-dimensional point cross-correlogram, is also described.

Type
Research Articles
Copyright
Copyright © Cambridge University Press 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Clark, P.J. & Evans, F.C. (1954). Distance to nearest neighbour as a measure of spatial relationships in populations. Ecology 35, 445453.CrossRefGoogle Scholar
Cliff, A.D. & Ord, J.K. (1973). Spatial Autocorrelation. London: Pion Limited.Google Scholar
Diggle, P.J. (1983). Statistical Analysis of Spatial Point Patterns. London: Academic Press.Google Scholar
Diggle, P.J. (1986). Displaced amacrine cells in the retina of a rabbit:analysis of a bivariate spatial point pattern. Journal of Neuroscience Methods 18, 115125.CrossRefGoogle Scholar
Ripley, B.D. (1981). Spatial Statistics. New York: John Wiley.CrossRefGoogle Scholar
Rodieck, R.W. (1967). Maintained activity of cat retinal ganglion cells. Journal of Neurophysiology 30, 10431071.CrossRefGoogle ScholarPubMed
Rodieck, R.W. & Marshak, D.W. (1989). Spatial distribution of choline acetyl-transferase (ChAT) labeled cells in the macaque retina. Society of Neuroscience Abstracts 15, 1207.Google Scholar
Rodieck, R.W. & Watanabe, M. (1988). Morphology of ganglion cell types that project to the parvocellular laminae of the lateral geniculate nucleus, pretectum, and superior colliculus of primates. Society of Neuroscience Abstracts 14, 1120.Google Scholar
Rose, R.D. & Grimson, R.C. (1988). N-Dimensional clusters of neuronal somata: a statistical analysis. Society of Neuroscience Abstracts 14, 550.Google Scholar
Shapiro, M.B., Schein, S.J. & DeMonasterio, F.M. (1985). Regularity and structure of the spatial pattern of blue cones of macaque retina. Journal of the American Statistical Association 80, 803812.CrossRefGoogle Scholar
Vaney, D.I., Peichl, L. & Boycott, B.B. (1981). Matching populations of amacrine cells in the inner nuclear and ganglion cell layers of the rabbit retina. Journal of Comparative Neurology 199, 373391.CrossRefGoogle ScholarPubMed
Voigt, T. (1986). Cholinergic amacrine cells in the rat retina. Journal of Comparative Neurology 248, 1935.CrossRefGoogle ScholarPubMed
Wê;ssle, H. & Riemann, H.J. (1978). The mosaic of nerve cells in the mammalian retina. Proceedings of the Royal Society B (Biology) 200, 441461.Google Scholar
Zar, J.H. (1974). Biostatistical Analysis. Englewood Cliffs, New Jersey: Prentice-Hall, Inc.Google Scholar