Gecko's Neural Information Recording And Feature Extraction

Bionic robot lags far behind bio-robot in stability, flexibility, robust, environmental adaptation and efficiency of energy when moving in complex environment. Biological robotics, which is to modulate animal's locomotion, has become an attractive direction in robotics researches. The lizard Gekko gecko is appropriate for bio-robot because of its excellent locomotion abilities on three-dimensional terrain and high load-carrying abilities. In the animal evolution, the lower animal usually has more sensitive olfaction. For a reptile, gecko's sensitive olfaction plays an important role in foraging and social interactions. It may be practical to modulate the animal's behavior by manipulating its odor sense. In order to reach this target, it is essential to study the animal behaviors and neural responses induced by olfactory stimuli. The researches of this thesis, including studies on odor-induced behavior, olfactory neural signal extracellular recording and pattern analysis in gecko, are full of challenges, and some method, for example, gecko's olfactory extracellular recording, was original work.During a long-term observation, we noticed that honey might be attractive to geckos, and amyl acetate might serve oppositely. The significance of odor influence was investigated by conditioned place studies. The smell of amyl acetate caused significant decrease of retention period in the behavior chamber. The result confirms that amyl acetate is disliked by geckos.The gecko's olfactory bulb is small, thus some key technologies must be solved before extracellular recording. Microelectrodes were developed with micro-wire and tested carefully. The skull above olfactory bulbs, duramater and arachnoid was removed to ensure the advancing of microelectordes. A signal acquisition system was set up to record both the neural signal and stimulation signal. Finally, the recording sites were verified by tissues.A multi-channel extracellular signal recording and analyzing system was developed to overcome the shortage of currently used equipment. The micorelectorde amplifier in the system includes high input impedance, large gain, and low noise. The performance of the unit is comparable to that of commercial products. Furthermore, for its smaller size, the unit is suitable for recording in freely behaving animals. A virtual instrument for signal recording developed with LabVIEW has functions of online spike detection and fire rate counting. The grid-based clustering method was improved and result in significant acceleration of spike sorting over valley seeking method. A toolbox for offline spike analysis built in MATLAB, is capable of the whole procedure of spike analysis, spike sorting, spike train analysis, etc. The toolbox provides a flexible batch processing mode, which can significantly accelerate the analysis when data set is large. This system makes the extracellular recording on gecko olfactory bulb possible.The olfactory bulb is the crucial area for neural information transferring and processing during odor identification in animals. The neural responses of geckos'olfactory bulbs to amyl acetate were examined by extracellular recording. The positions of recording sites were confirmed by tissue slicing. Response patterns could be classified into no response, suppression, and excitation. The excited neurons could be further classified into 4 subtypes by temporal patterns, long term excitation, short term excitation, delayed response and neurons excited when cancelling stimulation. More than half of neurons showed excitation, and most of excited neurons retained excitatory during 120-s stimulation. The neural responses elicited by amyl acetate could be found generally at the rostral part and the ventral side of caudal part. The results provide fundamental information on locomotion modulation by stimulating the animal's olfactory neural system.