Universität zu Köln

Knops, Sascha Alexander (2013). A neuro-mechanical model for the switching of stepping direction and transitions between walking gaits in the stick insect. PhD thesis, Universität zu Köln.

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Abstract

In this study, a mathematical model for the locomotion of the stick insect is developed. This model takes physiological conditions into account and it is capable of mimicking biological relevant features. The model is predicated on the crucial role, that sensory feedback plays in the coordination of limbs during walking. Central Pattern Generators (CPGs), which produce the rhythm of locomotion, are affected by sensory influences between the segments. The activities of the CPGs are transferred by the motoneurons to the muscles. Starting with existing neuron models and neuronal network models, a neuro-mechanical model is developed that includes the coupling of segments inside of a leg as well as the coupling of multiple legs. Firstly, mechanical models concerning the motion of the three isolated main joints are derived. These mechanical models are fused with the neuronal one. Thus, they represent neuro-mechanical models for the single joints that are coupled via sensory feedback. By means of the introduction of a switching mechanism the model is able to produce forward, backward and sideward stepping of a middle leg. Through the junction of two stepping middle legs to the body of the modeled stick insect, curve walking sequences with different curvatures can be produced. By extending the model to the front and the hind leg, the structure of intersegmental connection between the legs during the tripod and tetrapod gait can be generated. The change of stepping direction can be brought about by changing one single central command. If the middle leg is stepping backwards, the curvature during turning is smaller than in the case of sideward stepping. Weakly inhibitory intersegmental connections show the most accommodating leg coordination during both the tetrapod and the tripod gait.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Knops, Sascha Alexander sknops0@uni-koeln.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-51200
Date:	April 2013
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Zoologisches Institut
Subjects:	Natural sciences and mathematics Mathematics
Uncontrolled Keywords:	Keywords Language stick insect English CPG English
Date of oral exam:	9 April 2013
Referee:	Name Academic Title Gruhn, Silvia Dr. rer. nat.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/5120