The distribution of spherical cells in the anteroventral cochlear nucleus of the guinea pig*
AbstractSeveral types of neuron arc found in Nissl-stained sections of the anteroventral cochlear nucleus (AVCN). From these one group, the spherical cells (Osen, 1969), can be readily distinguished from the remaining small and multipolar forms. The rostral pole of the AVCN has previously been subdivided into the large and the small spherical cell areas (in several mammals). In the present study of the guinea pig AVCN, spatial distributions of cell density, size, and shape have been investigated. These have been used to test whether the subdivision made on the basis of morphological differences' in the spherical cells is valid, or whether there is a gradual gradient in these features. This analysis has shown that although variations in cell size and shape are observed, the spherical cell area cannot be partitioned on these grounds. There is, however, a graded increase in spherical cell packing density towards the rostral pole of the AVCN, with proportionately fewer of the other cell types present. Acknowledgements This work has been supported by a MRC programme grant to Prof. E. F. Evans and by a Wellcome Trust Travel Grant to C.M.H. which enabled her to visit Dr K. K. Osen, whose help and encouragement arc gratefully acknowledged. C.M.H. is also grateful to Dr J. C. Adams for a useful discussion of these results and to Dr D. N. Furness for commenting upon the manuscript. Wc also thank Mr S. Murray for technical assistance.