My doctoral research under the direction of Sasha Zill at the Marshall University School of Medicine focused on understanding the role of load detecting sense organs in pattern generation of locomotor behaviors.
I was interested in the leg control local circuit as well as the overall control of hexapod gait. I preformed single wire electroneurogram recordings from the peripheral nerves in the cockroach to determine sensory responses of the trochanteral campaniform sensilla. Additional recordings were placed in various muscles of the legs to determine how sensory input modulated motor output [1-3]. Analyses of the sensilla recordings found that sensory loading information specifically determined the firing rate of the extensor muscles of the femur. I also determined that load detectors can provide backup positional information depending on whether the leg was in swing or stance phase . When a leg was severed distal to the campaniform sensilla the firing rate of extensor muscles in remaining legs could be controlled by the input from the sensilla in the proximal severed leg . This contributed to regulation the subsequent changes in gait exhibited in the remaining legs. These experiments were performed on cockroaches that had small neodymium magnets attached to their dorsal thorax. A magnetic field could increase or decrease the loading on the organs. While attached with magnets, the animals were supported over a custom-made cockroach treadmill and had small reflective paint markers painted on each leg segment. These reflective markers were filmed using high speed video and digitized using Vicon motion capture software to determine leg movements in three dimensions.
Utilizing the biomechanics and neurophysiology of insect walking I provided control information to aid in the development biologically inspired robotic locomotor controllers and smart prosthetics in collaboration with the Case Western University Biologically Inspired Robotics Lab and the US Navy.