This volume is the issue of the symposium 'Theoretical Approaches to Complex systems', held in Tlibingen on June 11 and 12, 1977. The meeting was dedicated to the late Ernst Pfaffelhuber of the Institute for Information Sciences, University of Tlibingen, in memory of his con- tributions to information theory, physics, and biology and of his many fruitful contacts with the Tlibingen scientists gathered on this occa- sion. We would like to express our gratitude to all participants for their willingness to offer a weekend, for their help and the care they took in writing a contribution to this volume. R. Heim G. Palm CONTENTS Introduction H. Hahn 3 Existence Criteria for Bifurcations as Stability Criteria for Critical Nonlinear Control Systems G. Palm Asymptotic System Analysis and Goal Functions 51 O. E. ROssler and P. J. Ortoleva 57 Strange Attractors in 3-Variable Reaction Systems w. u. an der Heiden 75 Structures of Excitation and Inhibition T. Poggio and V. Torre 89 A new Approach to Synaptic Interactions W. Reichardt Figure-Ground Discrimination by the Visual **...**. *. ** 117 System of the Fly M. Conrad Evolution of the Adaptive Landscape ********. *. **** 147 V.
Braitenberg Cell Assemblies in the Cerebral Cortex *. ****. *. ***** 171 D. Varju Excitatory and Inhibitory Processes Giving Rise ********* 189 to the Delayed Response in the Retinal Ganglion Cell of the Frog R. Heim 209 On Constrained Transinformation Functions M.