Cat Retinal Ganglia Data
Point pattern of retinal ganglion cells identified as `on' or `off'. A marked point pattern.
An object of class
representing the point pattern of cell locations.
x Cartesian $x$-coordinate of cell
y Cartesian $y$-coordinate of cell
marks factor with levels
indicating ``off'' and ``on'' cells
ppp.object for details of the format.
W"assle et al (1981), data supplied by Peter Diggle
The data represent a pattern of beta-type ganglion cells in the retina of a cat recorded by W"assle et al. (1981). The window is a rectangle $(0,1) \times (0, .7533)$ mm approximately.
Beta cells are associated with the resolution of fine detail in the cat's visual system. They can be classified anatomically as ``on'' or ``off''. Statistical independence of the ``on''- and ``off''-components would strengthen the claim that there are two separate channels for ``brightness'' and ``darkness'' as postulated by Hering in 1874. For details see Waessle et al (1981).
These data have been analysed by Diggle (1986) and Van Lieshout and Baddeley (1999).
Diggle, P. J. (1986). Displaced amacrine cells in the retina of a rabbit : analysis of a bivariate spatial point pattern. J. Neurosci. Meth. 18, 115--125. Van Lieshout, M.N.M. and Baddeley, A.J. (1999) Indices of dependence between types in multivariate point patterns. Scandinavian Journal of Statistics 26, 511--532.
W"assle, H., Boycott, B. B. & Illing, R.-B. (1981). Morphology and mosaic of on- and off-beta cells in the cat retina and some functional considerations. Proc. Roy. Soc. London Ser. B 212, 177--195.