catWaessle             package:spatstat             R Documentation

_C_a_t _R_e_t_i_n_a _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     Point pattern of retinal ganglion cells identified as `on' or
     `off'. A marked point pattern.

_U_s_a_g_e:

     data(catWaessle)

_F_o_r_m_a_t:

     An object of class `"ppp"' representing the point pattern of cell
     locations. Entries include

       `x'      Cartesian x-coordinate of cell
       `y'      Cartesian y-coordinate of cell
       `marks'  factor with levels 0 or 1 indicating ``off'' and ``on'' cells

     See `ppp.object' for details of the format.

_N_o_t_e_s:

     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) x (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.

_S_o_u_r_c_e:

     W\"assle et al (1981), data supplied by Peter Diggle

_R_e_f_e_r_e_n_c_e_s:

     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.

