Uni-cellular integration of complex spatial information in slime moulds and ciliates.

Single-celled organisms show a fascinating faculty for integrating spatial information and adapting their behaviour accordingly. As such they are of potential interest for elucidating fundamental mechanisms of developmental biology. In this mini-review we highlight current research on two organisms, the true slime mould Physarum polycephalum and the ciliates Paramecium and Tetrahymena. For each of these, we present a case study how applying physical principles to explain behaviour can lead to the understanding of general principles possibly relevant to developmental biology.

Physarum inspires research beyond biomimetic algorithms: Reply to comments on "Does being multi-headed make you better at solving problems?"

We look at a recent expansion of Physarum research from inspiring biomimetic algorithms to serving as a model organism in the evolutionary study of perception, memory, learning, and decision making.

Does being multi-headed make you better at solving problems? A survey of Physarum-based models and computations.

Physarum polycephalum, a single-celled, multinucleate slime mould, is a seemingly simple organism, yet it exhibits quasi-intelligent behaviour during extension, foraging, and as it adapts to dynamic environments. For these reasons, Physarum is an attractive target for modelling with the underlying goal to uncover the physiological mechanisms behind the exhibited quasi-intelligence and/or to devise novel algorithms for solving complex computational problems. The recent increase in modelling studies on Physarum has prompted us to review the latest developments in this field in the context of modelling and computing alike. Specifically, we cover models based on (i) morphology, (ii) taxis, and (iii) positive feedback dynamics found in top-down and bottom-up modelling techniques. We also survey the application of each of these core features of Physarum to solving difficult computational problems with real-world applications. Finally, we highlight some open problems in the field and present directions for future research.

Current reinforcement model reproduces center-in-center vein trajectory of Physarum polycephalum.

Vein networks span the whole body of the amoeboid organism in the plasmodial slime mould Physarum polycephalum, and the network topology is rearranged within an hour in response to spatio-temporal variations of the environment. It has been reported that this tube morphogenesis is capable of solving mazes, and a mathematical model, named the 'current reinforcement rule', was proposed based on the adaptability of the veins. Although it is known that this model works well for reproducing some key characters of the organism's maze-solving behaviour, one important issue is still open: In the real organism, the thick veins tend to trace the shortest possible route by cutting the corners at the turn of corridors, following a center-in-center trajectory, but it has not yet been examined whether this feature also appears in the mathematical model, using corridors of finite width. In this report, we confirm that the mathematical model reproduces the center-in-center trajectory of veins around corners observed in the maze-solving experiment.