Design, Fabrication and Development of a Novel Flexible Electromyographic Electrode Array to Study Neural Control of Adaptive Locomotion in Soft-bodied Animals.
Metallo, Cinzia.
2013
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Abstract: Recent major advances in understanding the organizational principles underlying motor control have focused on a small number of animal species with stiff articulated skeletons. These model systems have the advantage of easily quantifiable mechanics but the neural codes underlying different movements are difficult to characterize because they typically involve a large population of neuron... read mores controlling each muscle. This arrangement also makes it difficult to study how neural codes drive adaptive changes in behavior. This problem is highly simplified in the larval stage of the tobacco hawkmoth Manduca sexta because of its unique motor innervation pattern: each muscle is innervated by one, occasionally two, excitatory motor neurons. This arrangement allows the electrical activity of each muscle to be mapped to individual motor neurons. Furthermore, there is no complicating influence of inhibitory activity. As a result, by correlating electromyographic (EMG) events to spikes in motor neuron activity, muscle activation patterns can be converted into specific motor neuron activation patterns. Using these patterns of spike activity, the mechanical responses of the muscles during natural strain cycles can then be quantified through in-vitro work loop analysis. To acquire motor patterns underlying adaptive locomotion, I employed a newly developed flexible micro-electrode array specifically designed to record high resolution muscle activity from Manduca muscles during crawling and climbing. Because of the high signal selectivity of the electrode array, it was possible to identify single excitatory junction potentials (EJP) within the composite EMG signals and relate the firing activity of single motor neurons to behavior. The hypothesis that soft-bodied animals like Manduca exploit self-adaptive properties of muscles to simplify motor control when presented with environmental changes, such as changes in crawling orientation, was tested. Not only were changes in Manduca crawling kinematics identified for the first time, but the timing of muscle activity was also found to be highly dependent of the orientation of the plane of motion, suggesting a more direct involvement of the CNS in Manduca adaptive behavior than previously hypothesized.
Thesis (Ph.D.)--Tufts University, 2013.
Submitted to the Dept. of Neuroscience.
Advisor: Barry Trimmer.
Committee: Daniel Cox, Eric Frank, and Robert Olberg.
Keywords: Neurosciences, Biology, and Biomedical engineering.read less - ID:
- x059cm15x
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