The brain evolved to control behavior, and locomotion is among the behaviors most critical to animal survival. The neural mechanisms of skilled locomotion have been studied for decades, yet recently developed technologies offer the opportunity to shine new light on this long studied behavior. I leveraged these technologies to develop a system for studying the behavioral strategies and neural mechanisms of skilled locomotion in mice. In Chapter 2, I use detailed 3D kinematic tracking and behavioral modelling to describe a rapid sensorimotor decision that determines the kinematic strategies used by mice to step over obstacles. Despite the whisker dependency of this behavior, performance is minimally affected by manipulations of whisker sensory cortex, whereas motor cortex manipulations impair but did not prevent obstacle clearance. Neither cortical manipulation substantially impacts the sensorimotor decision. In Chapter 3, we turn to the cerebellum. The cerebellum is thought to contribute to the coordination of movement, as evinced by the locomotor deficits that are a hallmark of cerebellar ataxia. However, much cerebellar research has focused on simple behaviors involving single body parts. Furthermore, the recent discovery of reward signals in the cerebellar cortex has drawn attention to its potential non-motor functions, but whether such signals exist in the output of the cerebellum is unknown. We conducted an electrophysiological survey of the deep cerebellar nuclei to characterize the signals communicated by the cerebellum to downstream structures. Preliminary analyses from this ongoing work suggest that cerebellar output is dominated by orofacial and locomotor signals, whereas reward related modulations are largely accounted for by the behavioral correlates of reward delivery. Collectively, these results demonstrate that quantitative whole body analyses of ethologically inspired behaviors can enhance our understanding of the neural control of sensorimotor behaviors.

There is a high prevalence of musculoskeletal symptoms (MSS) among manual material handling (MMH) workers. However, limited investigations have been undertaken among one large group of workers using a particular MMH method called traditional posterior load carriage (PLC). Such load carriage is typically done without the use of an assistive device (e.g., backpack) in developing countries, and involves exposure to known risk factors for MSS such as heavy loads, non-neutral postures, and high levels of repetition. The current work was completed to investigate the characteristics of the PLC task and physical effects on workers, and to evaluate a practical intervention that may help improve the task. The first study investigated, through structured interviews with 108 workers, the types, prevalence, and impacts of MSS. PLC workers incur a relatively high MSS burden, primarily in the lower back, but also in the feet, knees, shoulders, and neck. These MSS were reported to interfere with daily activity, but only few workers sought medical treatment. Workers suggested several task improvements including the use of a belt, hook, or backpack/frame, and changes in the carriage method. The second and third study investigated, in a laboratory setting involving nine healthy males, the effects of load mass and size, and the use of a simple intervention, respectively, on factors related to low back pain risks during PLC. Increasing load mass caused increased torso flexion, lumbosacral flexion moment, abdominal muscle activity, and torso movement stability in the frontal plane. Increasing load size also caused higher torso flexion, peak torso angular velocity and acceleration, and abdominal muscle activity. Complex interactive effects of load mass and size were found on paraspinal muscle activity and slip risk. The intervention, involving a simple frame to support a load, and use with a higher load placement was found to be potentially beneficial as indicated by reduced lumbosacral moment and ratings of perceived discomfort in several anatomical regions compared to the traditional PLC. Outcomes of this research can facilitate future ergonomic guidelines and interventions to improve working conditions and occupational health and safety for PLC workers. / Ph. D.

This paper deals with techniques for acquiring data for character animation driven from video. Among other, it also presents several Motion Capture systems and animation data formats BVH and CSM. It also contains an example application demonstrating attained accomplishments. These are reviewed and there is instituted a course of future proceeding.

付記する学位プログラム名: デザイン学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21755号 / 工博第4572号 / 新制||工||1713(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 小森 雅晴, 教授 松野 文俊, 教授 松原 厚 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.

Spinal cord injury (SCI) causes life-long neurological impairment, with loss of sensory and motor function distal to the point of injury. There are approximately 300,000 patients living with SCI in the United States, and currently no effective treatment, reducing their quality of life. Amongst other things, proprioception, which has been determined essential for normal locomotion, can be lost with SCI. Epidural Electric Stimulation (EES), that is thought to excite large diameter afferent fibers (LDAF), has been found to improve recovery from spinal cord injury in conjunction with movement rehabilitation in animal models and humans. This represents an exciting new approach to help these patients. However, many open questions remain about how and why EES works. Chief among them are 1) which of the afferent fibers are necessary and sufficient to promote better recovery, and 2) what are the mechanisms of plasticity in the spinal cord that underly improvement. Here, we sought to address the first question by using viral and genetic tools to begin to target specific subsets of LDAF. First, we use a viral vector that preferably transduces only in the large diameter afferent fibers (LDAF) in the Dorsal Root Ganglia (DRG), and then specifically only the proprioceptors within the LDAF, by using a transgenic rat line that expresses Cre recombinase in Parvalbumin, a marker for proprioceptive neurons in the DRG. This approach consists of using the chemogenetic modulator of neuronal activity Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), which are activated by a putatively inert drug, clozapine-N-oxide (CNO), that crosses the blood brain barrier. While we were able to specifically target LDAF with excitatory DREADDs in L3-L5 DRGs in wild type rats, we were unsuccessful at specifically targeting proprioceptors by using the Pvalb-iCre rat line. Additionally, we studied the effect of exciting LDAF on rats with a 200KDyn SCI. CNO withdrawal on the week 7 stage of the recovery was associated with worse ladder performance than the previous and following weeks, as well as worse kinematic behavior of the same week on lower speeds in ankle movement. These results suggest that DREADDs activation is necessary for changes in movement at longer times post injury. It does not rule out that plasticity in neural circuitry has occurred but suggests that plasticity may rely on afferent activation. Finally, we sought to develop new methods to overcome skin motion artifact in rat kinematics by tattooing the knee area under the skin and recording infrared high-speed videos of moving rats which would correct joint calculations beyond just triangulation methods, as well as a novel MATLAB application that can accurately and reliably perform automated H-Reflex measurements, test the stimulating electrodes, and carry out typical instantaneous analyses, which in return allows for faster data collection with reduced human error, and subsequently result in higher research quality. / Bioengineering

No description available.

Exoskeletons can be helpful to patients who suffer from muscular dysfunctions. Recent studies focus on exoskeletons which can perform complex human movements. Further analysis is needed in the area of unusual movements like obstacle clearance to design an assistive device which can deliver effective aid to the intended patients in need. It is necessary to understand the behavior of lower limb muscles when they are subjected to complex physical activity. This study is aimed to analyze the activity of muscles in the lower body during obstacle clearance. Two different levels of obstacle have been maintained, analyzed and compared with a normal gait. The muscle groups taken for the study are quadriceps, hamstrings and plantar flexors. The primary hypothesis is that the quadriceps, Hamstrings, and dorsi flexors tend to have higher muscle activation while performing a complex physical task like stepping over an obstacle with the heights of 20 cms and 36 cms than a normal walking gait. The muscles from those three mentioned groups contribute more to the obstacle clearance compare to that of normal gait. Further research is recommended to expand knowledge about muscle activation.

No description available.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24465号 / 理博第4964号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 平﨑 鋭矢, 教授 髙井 正成, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM