Reversible silencing of spinal neurons unmasks a left-right coordination continuum.

This dissertation is focused on dissecting the functional role of two anatomically-defined pathways in the adult rat spinal cord. A TetOn dual virus system was used to selectively and reversibly induce enhanced tetanus neurotoxin expression in L2 neurons that project to L5 (L2-L5) or C6 (long ascending propriospinal neurons, LAPNs). Results focus on the changes observed during overground locomotion. The dissertation is divided into four chapters. Chapter One is a focused introduction to locomotion, including its broad description, the central mechanisms of its expression, how genetic-based approaches defined these mechanisms, and the limitations in these approaches. It concludes with details of the silencing paradigm used here and a summary of the main findings. Chapter Two describes the functional consequences of silencing L2-L5 interneurons. The focus is on selective disruption of hindlimb coordination during overground locomotion, revealing a continuum from walk to hop. These changes are independent of speed, step frequency, and other spatiotemporal features of gait. Left-right alternation was restored during swimming and stereotypic exploration, suggesting a task-specific role. Silencing L2-L5 interneurons partially uncoupled the hindlimbs, allowing spontaneous shifts in coordination on a step-by-step basis. It is proposed this pathway distributes temporal information for left-right hindlimb alternation, securing effective coordination in a context-dependent manner. Chapter Three focuses on the consequences of silencing LAPNs.Three patterns of interlimb coupling are disrupted: left-right forelimb, left-right hindlimb, and contralateral hindlimb-forelimb coordination. Observed again was a context-dependent continuum from walk-to-hop, irrespective of step frequency, speed, and the salient features that define locomotion. However, instead of spontaneous shifts in coordination as observed from L2-L5 interneuron silencing, the breadth of coupling patterns expressed were maintained on a step-by-step basis. It is proposed that this ascending, inter-enlargement pathway distributes temporal information required for left-right alternation at the shoulder and pelvic girdles in a context-dependent manner. Collectively, these data suggest that L2-L5 interneurons and LAPNs are key pathways that distribute left-right patterning information throughout the neuraxis. The functional role(s) of these pathways are exquisitely gated to the context at hand, suggesting that the locomotor circuitry undergoes functional reorganization thereby endowing or masking the silencing-induced disruptions to interlimb coordination

2016 - The Twenty-first Annual Symposium of Student Scholars

The full program book from the Twenty-first Annual Symposium of Student Scholars, held on April 21, 2016. Includes abstracts from the presentations and posters.https://digitalcommons.kennesaw.edu/sssprograms/1015/thumbnail.jp

Artificial intelligence for neurodegenerative experimental models

INTRODUCTION: Experimental models are essential tools in neurodegenerative disease research. However, the translation of insights and drugs discovered in model systems has proven immensely challenging, marred by high failure rates in human clinical trials. METHODS: Here we review the application of artificial intelligence (AI) and machine learning (ML) in experimental medicine for dementia research. RESULTS: Considering the specific challenges of reproducibility and translation between other species or model systems and human biology in preclinical dementia research, we highlight best practices and resources that can be leveraged to quantify and evaluate translatability. We then evaluate how AI and ML approaches could be applied to enhance both cross-model reproducibility and translation to human biology, while sustaining biological interpretability. DISCUSSION: AI and ML approaches in experimental medicine remain in their infancy. However, they have great potential to strengthen preclinical research and translation if based upon adequate, robust, and reproducible experimental data. HIGHLIGHTS: There are increasing applications of AI in experimental medicine. We identified issues in reproducibility, cross-species translation, and data curation in the field. Our review highlights data resources and AI approaches as solutions. Multi-omics analysis with AI offers exciting future possibilities in drug discovery

Social attention in young children with autism spectrum disorder: Investigating cross-contextual gaze behaviours, and their relationship to autism severity, cognitive skills and social functioning

Social communication and interaction challenges are characteristic of autism spectrum disorder (ASD). Social attention has emerged to be an important behavioural phenotype in ASD, with accumulating evidence suggesting associations with social functioning and developmental outcomes. However, research gaps remain concerning the nature of social attention, the variability demonstrated across different experimental tasks and social contexts, and the ecologically validity of research methods. This thesis aimed to address these substantive and methodological issues by examining social attention patterns in a young cohort of autistic children, and their age-matched neurotypical peers, across three experimental contexts: 1) a traditional, eye-tracking task with static stimuli, 2) a novel, dynamic eye-tracking task incorporating shared book reading (SBR), and 3) an evaluation of the association in social attention across the two eye-tracking tasks and a play-based social interaction task. In Chapter 2, the influence of circumscribed interests (CI) on social attention patterns was investigated. The results of this study suggested there to be a reduced role for CIs and atypical attention patterns in both social and non-social domains. In Chapter 3, a novel SBR task was developed as a dynamic, ecologically relevant eye-tracking task designed to assess social and joint attention behaviours. Results indicated reduced social and joint attention behaviours, in conjunction with increased attention to non-salient background objects in autistic children. Associations between reduced social attention and poorer social functioning and cognitive skills were also evident in this cohort. In Chapter 4, the social attention patterns of the autistic cohort as measured by the two previous eye tracking tasks were correlated with these patterns in a live, play-based social interaction task between a researcher and the autistic child. Cross-contextual associations in social attention between the social interaction and dynamic tasks, and the dynamic and static tasks were observed. In contrast, there was no significant association in social attention patterns between the social interaction and static tasks. These outcomes contribute new insights into the social attention behaviours of autistic children, and evidence in favor of examining these behaviours in ecologically relevant contexts. They also contribute to evidence associating social attention with autism symptomatology and cognitive functioning. Ultimately, the outcomes of this research may improve our understanding of the needs of autistic children across social, cognitive and adaptive functioning domains

Automated Correlative Light and Electron Microscopy using FIB-SEM as a tool to screen for ultrastructural phenotypes

In Correlative Light and Electron Microscopy (CLEM), two imaging modalities are combined to take advantage of the localization capabilities of light microscopy (LM) to guide the capture of high-resolution details in the electron microscope (EM). However, traditional approaches have proven to be very laborious, thus yielding a too low throughput for quantitative or exploratory studies of populations. Recently, in the electron microscopy field, FIB-SEM (Focused Ion Beam -Scanning Electron Microscope) tomography has emerged as a flexible method that enables semi-automated 3D volume acquisitions. During my thesis, I developed CLEMSite, a tool that takes advantage of the semi-automation and scanning capabilities of the FIB-SEM to automatically acquire volumes of adherent cultured cells. CLEMSite is a combination of computer vision and machine learning applications with a library for controlling the microscope ( product from a collaboration with Carl Zeiss GmbH and Fibics Inc.). Thanks to this, the microscope was able to automatically track, find and acquire cell regions previously identified in the light microscope. More specifically, two main modules were implemented. First, a correlation module was designed to detect and record reference points from a grid pattern present on the culture substrate in both modalities (LM and EM). Second, I designed a module that retrieves the regions of interest in the FIB-SEM and that drives the acquisition of image stacks between different targets in an unattended fashion. The automated CLEM approach is demonstrated on a project where 3D EM volumes are examined upon multiple siRNA treatments for knocking down genes involved in the morphogenesis of the Golgi apparatus. Additionally, the power of CLEM approaches using FIB-SEM is demonstrated with the detailed structural analysis of two events: the breakage of the nuclear envelope within constricted cells and an intriguing catastrophic DNA Damage Response in binucleated cells. Our results demonstrate that executing high throughput volume acquisition in electron microscopy is possible and that EM can provide incredible insights to guide new biological discoveries

Research and Creative Activity, July 1, 2020-June 30, 2021: Major Sponsored Programs and Faculty Accomplishments in Research and Creative Activity, University of Nebraska-Lincoln

Foreword by Bob Wilhelm, Vice Chancellor for Research and Economic Development, University of Nebraska-Lincoln: This booklet highlights successes in research, scholarship and creative activity by University of Nebraska–Lincoln faculty during the fiscal year running July 1, 2020, to June 30, 2021. It lists investigators, project titles and funding sources on major grants and sponsored awards received during the year; fellowships and other recognitions and honors bestowed on our faculty; books and chapters published by faculty; performances, exhibitions and other examples of creative activity; patents and licensing agreements issued; National Science Foundation I-CORPS teams; and peer-reviewed journal articles and conference presentations. In recognition of the important role faculty have in the undergraduate experience at Nebraska, this booklet notes the students and mentors participating in the Undergraduate Creative Activities and Research Experience (UCARE) and the First-Year Research Experience (FYRE) programs. While metrics cannot convey the full impact of our work, they are tangible measures of growth. A few achievements of note: • UNL achieved a record $320 million in total research expenditures in FY 2020, a 43• Our faculty earned 1,508 sponsored research awards in FY 2020. University-sponsored industry activity also spurred economic growth for Nebraska. • Nebraska Innovation Campus created 1,948 jobs statewide and had a total economic impact of$372 million. • Industry sponsorship supported $19.2 million in research expenditures. • NUtech Ventures brought in$6.48 million in licensing income. I applaud the Nebraska Research community for its determination and commitment during a challenging year. Your hard work has made it possible for our momentum to continue growing. Our university is poised for even greater success. The Grand Challenges initiative provides a framework for developing bold ideas to solve society’s greatest issues, which is how we will have the greatest impact as an institution. Please visit research.unl.edu/grandchallenges to learn more. We’re also renewing our campus commitment to a journey of anti-racism and racial equity, which is among the most important work we’ll do. I am pleased to present this record of accomplishments. Contents Awards of $5 Million or More Awards of$1 Million to $4,999,999 Awards of$250,000 to $999,999 50 Early Career Awards Arts and Humanities Awards of$250,000 or More Arts and Humanities Awards of $50,000 to$249,999 Arts and Humanities Awards of $5,000 to$49,999 Patents License Agreements National Science Foundation Innovation Corps Teams Creative Activity Books Recognitions and Honors Journal Articles 105 Conference Presentations UCARE and FYRE Projects Glossar