Preliminary Research Of Central Pattern Generator (CPG) Neural Network Of Gekko Gecko’s Hindlimb

The Gekko gecko has become an ideal model for bio-inspired robot because of its excellent threedimensional obstacle-free locomotion ability. But at present, the gecko-inspired robot designed athome and broad is mainly based on the path planning method with poor flexibility and autonomy andhardly can be applied in non-structural environment. Vertebrates show outstanding motion controlcapability. Their locomotion is modulated by the central pattern generator (CPG) in spinal cord.Gekko gecko crawls forward and its toes show great capability of adduction (attachment) andabduction (detachment). Thus the control mechanism of CPG neural network must be different fromthat of general quadrupeds. It’s necessary to do thorough research on CPG neural network of gecko todevelop gecko-inspired robot based on CPG.The structure of spine and spinal cord of gecko were studied detailedly in this paper. By themethod of chemical immersion, a transparent gecko skeleton with good integrity and permeabilitywas fabricated. Based on the comprehensive anatomy of spinal cord, forelimb and hindlimb, it hasbeen confirmed that C5-C8segment was cervical enlargement and L12-S2segment was lumbarenlargement. The spinal nerve from these segments controlled the motion of forelimb and hindlimbrespectively. Through the histological section of lumbar enlargement, the distribution of differenttypes of neurons was calibrated.A spinal adaptor of gecko was developed, which was composed of vertebral clamp, movingblock and support unit. Through the bilateral clamping to the concave curved structure betweenformer zygapophysis and later zygapophysis or to the intervertebral foramen (sacral vertebra), theexperimental area could be positioned well. Anatomic experiment of spinal cord in different segmentsand intrathecal microinjection experiment verified that the adaptor can meet the needs of research.The spinal preparation of gecko in vivo was made with the adaptor designed. The preliminaryresearch on CPG neural network of gecko was carried out by the method of recording commonperoneal nerve under the condition of each segment of lumbar enlargement being micro stimulated bydifferent concentrations of sodium glutamate. Rhythmic discharge of common peroneal nerve couldbe induced following the stimulation of L12with10mM sodium glutamate or the stimulation of L13with20mM sodium glutamate. Histological sections showed that the stimulation site was in the areaof interneuron. From the statistical analysis of the signal acquainted, it has been found that theamplitude and frequency of discharge depend on the stimulation concentration. What’s more, several important conclusions were achieved. For example, glutamate could induce the rhythmic locomotionof gecko, L12and L13segments contained the network for rhythm generation, the reciprocalinhibition between two sides of spinal cord wasn’t the essential condition for rhythm generation, et al.