Universität zu Köln

Rosenbaum, Philipp, Schmitz, Josef, Schmidt, Joachim and Bueschges, Ansgar (2015). Task-dependent modification of leg motor neuron synaptic input underlying changes in walking direction and walking speed. J. Neurophysiol., 114 (2). S. 1090 - 1102. BETHESDA: AMER PHYSIOLOGICAL SOC. ISSN 1522-1598

Full text not available from this repository.

Abstract

Animals modify their behavior constantly to perform adequately in their environment. In terrestrial locomotion many forms of adaptation exist. Two tasks are changes of walking direction and walking speed. We investigated these two changes in motor output in the stick insect Cuniculina impigra to see how they are brought about at the level of leg motor neurons. We used a semi-intact preparation in which we can record intracellularly from leg motor neurons during walking. In this single-leg preparation the middle leg of the animal steps in a vertical plane on a treadwheel. Stimulation of either abdomen or head reliably elicits fictive forward or backward motor activity, respectively, in the fixed and otherwise deafferented thorax-coxa joint. With a change of walking direction only thorax-coxa-joint motor neurons protractor and retractor changed their activity. The protractor switched from swing activity during forward to stance activity during backward walking, and the retractor from stance to swing. This phase switch was due to corresponding change of phasic synaptic inputs from inhibitory to excitatory and vice versa at specific phases of the step cycle. In addition to phasic synaptic input a tonic depolarization of the motor neurons was present. Analysis of changes in stepping velocity during stance showed only a significant correlation to flexor motor neuron activity, but not to that of retractor and depressor motor neurons during forward walking. These results show that different tasks in the stick insect walking system are generated by altering synaptic inputs to specific leg joint motor neurons only.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Rosenbaum, Philipp UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmitz, Josef UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmidt, Joachim UNSPECIFIED UNSPECIFIED UNSPECIFIED Bueschges, Ansgar UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-397273
DOI:	10.1152/jn.00006.2015
Journal or Publication Title:	J. Neurophysiol.
Volume:	114
Number:	2
Page Range:	S. 1090 - 1102
Date:	2015
Publisher:	AMER PHYSIOLOGICAL SOC
Place of Publication:	BETHESDA
ISSN:	1522-1598
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language STICK INSECT LEG; BACKWARD QUADRUPEDAL WALKING; TIBIA-CONTROL-SYSTEM; FICTIVE LOCOMOTION; INHIBITORY MOTONEURONS; PATTERN GENERATION; ADAPTIVE-CONTROL; INTERJOINT COORDINATION; SENSORIMOTOR PATHWAYS; SEARCHING MOVEMENTS Multiple languages Neurosciences; Physiology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/39727