PUB - Publikationen an der Universität Bielefeld

The faculty to generate patterns is a basic feature of living systems. Such patterns may be generated as fixed spatial patterns mainly used for the development of morphological structures, which will be mentioned here only briefly, or as spatio- temporal patterns as used in the context of controlling behaviors (see Herreros, Chapter 26, this volume). Here we address two types of patterns: (1) quasi- rhythmic patterns, typically applied in locomotion, and (2) non- rhythmic patterns used to control specific behaviors and to allow for switching between various behaviors. 1. Quasi- rhythmic patterns are typically found in locomotory behaviors which can be ordered in a series being characterized by increasing unpredictability of the environment, as are swimming, flying, running, walking on flat surfaces, and walking and climbing on cluttered, i.e. unpredictable surfaces (see chapters by Kruusmaa (44), Hedenström (32), Witte et al. (31), and Quinn and Ritzmann (42) in this volume). The corresponding controllers range along a continuum from those which produce patterns endogenously based on circular attractors, to pattern generators where the loop through the world plays a crucial role, i.e. where body and environment are part of the computational system. Patterns may result from explicit implementation or result as emergent properties. 2. A brain, when controlling various sequential behaviors, has to switch between different internal states characterized by their ability to select motor output (action selection) and to select sensory input (top- down attention). These states can be represented by the activation of various combinations of procedural memory elements, whereby various coalitions of individual elements typically form discrete (i.e. point- ) attractors and may be ordered in such a way that the complete system comprises a heterarchical structure.