Zebrafish is a frequently used model organism with an array of transgenic lines that have been used indevelopmental and physiological studies. We aim to generate novel transgenic zebrafish reporter lines to study subpopulations of spinal neurons in vivo. The gene editing system called CRISPR/Cas9 system was used to knock in reporter genes such as green fluorescent protein (GFP) or Gal4 transcription factor, to generate transgenic fish lines. Zebrafish embryos were injected with gRNAs targeting gabrb1 or nr4a2a and GFP or Gal4 plasmid, respectively. F0 larvae were screened, positive fish were raised until sexual maturity, and founders characterized to verify germline insertion. Three founders were found for gabrb1 and the location and the direction of the insert verified. The GFP expression was studied during development and differential expression patterns were identified whereas all founders had expression in brain and spinal cord. In parallel, positive fish from the Gal4 injections were raised and will be screened. Immunohistochemistry was performed to check if nr4a2a is expressed in the same cells as known neuronal markers. However, no co-localization was detected. The three gabrb1 founders identified in this study highlight the challenges into creating stable transgenic lines recapitulating true expression of the gene of interest. Sequencing, in-situ hybridization and immunohistochemistry should be performed to verify the line. A possible reason for the varying expression may be that through the knock-in we may interfere with regions regulating gene. The nr4a2a-Gal4 line will be used to perform functional studies. Those experiments will be performed using reporter genes, such as opsins or GCaMP, controlled by Upstream Activation Sequence (UAS). These transgenic lines will provide important insights regarding neuronal subpopulations that express gabrb1 and nr4a2a to unravelhow the locomotor network is formed.

The purpose of this study was to explore the differences in the aerobic response to wheeling between wheelchair dependent individuals and able-bodied individuals of similar genders and ages. Five wheelchair dependent men (WC) and five able-bodied men (AB) performed a 13 minute wheeling test (5 min. at rest, 8 min. wheeling) at 4.0 km∙hr-1. Heart rate (HR) and VO2 were recorded using a Vmax ST system during the constant speed test. There was no significant difference in HR or VO2 between the two groups during rest. Both HR and VO2 were higher for WC during exercise. The mean METS during exercise for WC and AB were 3.589 ± 0.516 and 2.726 ± 0.164, respectively. The results indicate that at a given workload a spinal cord injured wheelchair user will have a greater aerobic response than an able-bodied person in a wheelchair completing the same task.

Orientador: Rodrigo Vitório / Resumo: Introdução: Apesar dos correlatos neurais dos comprometimentos do andar associados ao envelhecimento não serem completamente compreendidos, estudos recentes apontam que idosos apresentam maior ativação do córtex pré-frontal (via indireta) durante o andar. Entretanto, os estudos existentes não consideram o processo de envelhecimento em um espectro mais amplo e, ao contrário, apresentam comparações limitadas a extremos de idade (adulto jovem X idoso). A compreensão da atividade neural do controle do andar no envelhecimento é importante para a identificação do momento em que as alterações inerentes ao envelhecimento afetam a atividade do córtex cerebral. Assim os objetivos deste estudo foram: (i) investigar os efeitos do envelhecimento na atividade do córtex pré-frontal (CPF) durante o andar usual, adaptativo e com tarefa dupla; e (ii) analisar a associação entre a atividade cortical e medidas do andar e de funções cognitivas. Materiais e Método: Noventa participantes foram avaliados, sendo 15 participantes sadios em cada grupo etário: 20-25, 30-35, 40-45, 50-55, 60-65 e 70-75 anos. Foram realizadas avaliações cognitivas, do andar e da atividade do CPF. Um sistema portátil de espectroscopia funcional de luz próxima ao infravermelho foi utilizado para o registro da atividade do CPF enquanto os participantes andavam em um circuito em três condições: andar usual, adaptativo (ultrapassagem de obstáculos) e com tarefa dupla. Um carpete com sensores de pressão foi posicionado em uma d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: Although the neural correlates of walking impairments associated with aging are not fully understood, recent studies indicate that the older adults present greater activation of the prefrontal cortex during walking. However, existing studies do not consider the aging process in a broader spectrum and, on the contrary, present limited comparisons to extremes of age (younger X older adult). Understanding the neural activity of walking control in aging is important to identify when the inherent changes in aging affect the activity of the cerebral cortex. Thus, the aims of this study were: (i) to investigate the effects of aging on the activity of the prefrontal cortex (PFC) during usual, adaptive and dual task walking; and (ii) to analyze the association of cortical activity with walk measures and cognitive functions. Materials and Methods: Ninety participants were evaluated, with 15 healthy participants in each age group: 20-25, 30-35, 40-45, 50-55, 60-65 and 70-75 years. Cognitive, walking and PFC activity assessments were performed. A portable near infrared functional spectroscopy system was used to record PFC activity while participants walked on a circuit in three conditions: usual, adaptive (obstacle avoidance) and dual task walking. A carpet with pressure sensors was positioned in one of the straight lines of the circuit to record walk parameters. ANCOVAs were used to analyze differences in oxyhemoglobin concentrations between groups and conditions; Two-way ... (Complete abstract click electronic access below) / Mestre

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In recent years, the field of Soft Robotics has grown exponentially resulting in a variety of different soft robot designs. A majority of the current soft robots can easily be split into two distinct categories: Navigation and Grasping. Navigation robots alter their body orientation to navigate around an environment. Grasping robots are designed to grasp a variety of unknown objects without damaging said object. However, only a few robots are able to demonstrate both aspects and even fewer robots are able to do both simultaneously. As thus, the goal of this thesis is to create a soft robot that is able to pick up and support an additional payload. This thesis will explore the challenges and difficulties that come with designing such a robot. For this thesis, we chose to simplify the manufacturing process making it easy to create and test different designs. We primarily used Pneumatic Network actuators for the majority of the soft robot. This allowed us to use a layered manufacturing approach to create the full robot. Finally, we split the robot into two main components which have their own purpose, which made it easy to test and design each component. Attached to this thesis are three different supplementary videos. The first one labeled "Walking Gaits" demonstrate how the robot is capable of moving forward. This video is comprised of several sections showing the full robot moving, just the base moving, and the full robot briefly moving as it supports a payload. The second video is labeled "Additional Walking". This video shows how the base can effectively move around a given environment. The final video if called "Grasping Method" which demonstrates the different grasping methods that the full robot uses to pick up objects. / 2021-06-03T00:00:00Z

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.

The purpose of the present study is to examine swimming position, gait, stroke speed, speed over distance, endurance, and willingness to enter water in four species of mice found in the Sacramento-San Joaquin River Delta of California; Mus musculus, Reithrodontomys megalotis longicaudus, Miorotus californicus acstuarius, and Peromyscus maniculatus gambelii.

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There is considerable evidence suggesting an innate linkage between the human perceptual and motor systems, which evolve together and assist one another in the production and coordination of movement. A major contributor to this relationship is optic flow, providing movement variables such as navigation, obstacle avoidance, and depth perception. The absence of optic flow leads to the decoupling of perception and action, which has been shown to contribute to decrements in human movement (i.e., negatively impacted locomotion and posture, and slower adaptation to gait perturbations). Despite the importance of maintaining this linkage, optic flow manipulations are often found to be underrepresented in locomotion literature when specifically related to rehabilitation training (i.e., treadmills). This may be a contributor to the lengthy and exhaustive treatment plans. The literature has shown instances where reintroducing optic flow into training protocols has shown larger gait improvements in shorter times than typical ambulation protocols, however, the strength of the perception-action linkage in adulthood is still not well understood and its impact not yet fully explored. Therefore, the current research program aims to fill this gap by evaluating how the reintroduction of optic flow into atypical gait training protocols in both healthy and gait-compromised individuals may provide evidence that could be used to enhance rehabilitative outcomes. This series of conceptually related experiments explores outcome enhancements through neuromuscular level changes (Study One), the recalibration process of perception-action given newly acquired physical constraints (Study Two), and on larger scale gait cycle performances in a rehabilitation setting (Study Three). It is hypothesized that perception- action coupling will lead to increases in neuromuscular elicitation in the absence of voluntary movement (Study One), assist the recalibration process to improve measures of spatial awareness and atypical gait parameters (Study Two), and finally, improve rehabilitative outcomes in a spinal cord injury (SCI) ambulation protocol, both objectively (i.e., gait parameters, dynamic balance, SCI measures) and subjectively (i.e., questionnaires) (Study Three). / Thesis / Master of Science (MSc)