* Corresponding author. Tel.: #31-20-5665481; fax: #31-20-6961006. E-mail address: j.van.pelt@nih.knaw.nl (J. van Pelt). Neurocomputing 38}40 (2001) 403}408 Modeling dendritic morphological complexity of deep layer cat superior colliculus neurons Jaap van Pelt*, Andreas Schierwagen, Harry B.M. Uylings Graduate School Neurosciences Amsterdam, Netherlands Institute for Brain Research, Meibergdreef 33, 1105 AZ Amsterdam, Netherlands Institute for Computer Science, University of Leipzig, D-04107 Leipzig, Germany Abstract Dendritic complexity of deep layer cat superior colliculus neurons has been studied by means of a stochastic model for dendritic outgrowth with randomly branching and elongating neurites. Branching probabilities are assumed to depend on the position and the number of segments in the growing tree. It is demonstrated that the shape properties of model generated dendrites conform closely to those of the observed trees. These "ndings make plausible that (i) dendritic development proceeds following a "rst phase of elongation and branching, and a second phase of elongation only, and (ii) newly formed segments after a branching event have a short initial length.  2001 Elsevier Science B.V. All rights reserved. Keywords: Stochastic growth model; Dendritic trees; Cat superior colliculus neurons; Dendritic development; Morphology 1. Introduction Dendritic branching patterns are complex structures with large variations in their shapes within and between di!erent classes of neurons. Recent modeling studies have demonstrated that typical shape properties may arise naturally from di!erences in neurite outgrowth and branching during dendritic development [7}10]. These studies of rat cortical layer 2/3 and layer 5 pyramidal basal dendrites and guinea pig cerebellar Purkinje cell dendritic trees have shown that the observed variation in morphological shapes was accurately reproduced by a stochastic process of neuritic 0925-2312/01/$ - see front matter  2001 Elsevier Science B.V. All rights reserved. PII:S0925-2312(01)00347-2