Department of Biomedical Engineering Posters and Presentations

Title

3D Morphological Analysis of Neurons in Hypoglossal Nucleus in Mouse Model of DiGeorge Syndrome

Document Type

Poster

Keywords

Imaging, Neuroscience, Analysis, Confocal

Publication Date

4-2017

Abstract

Pediatric dysphagia is a condition characterized by difficulties in feeding and swallowing in infants and children. The tongue is one of the structures involved in feeding and swallowing, and abnormalities in tongue control occur in patients suffering from dysphagia. Cranial nerve XII, hypoglossal nerve, is a nerve that originates from the hypoglossal nucleus in the brain stem and innervates the tongue; it is responsible for proper functionality of the tongue. DiGeorge Syndrome feeding and swallowing abnormalities occur in the early developmental stages of the disease. The goal of this research is to further identify morphological differences of neurons within the hypoglossal nucleus. These anatomical and physiological differences will be observed in wild type mice (WT) and in mice with a large deletion of genes (LgDel) that is equivalent to 22q11DS (the gene deletion causing DiGeorge Syndrome) in humans. These differences will be studied by evaluating parameters, such as volume and quantity of neurons in the hypoglossal nucleus. As well as, the dendritic lengths, sizes, and branching points will be analyzed as well the volume of individual neurons in the hypoglossal nucleus – which have undergone electrophysiological measurements and parameters

Utilizing confocal and fluorescence microscopy techniques with the ZEISS 710 confocal instrument, the student acquires 3D data sets that can be further analyzed. The images will then be observed to identify qualitative differences of the cells. Next, the images will be analyzed utilizing Imaris because Imaris contains options that allows users to import these image sets and reconstruct 3D structures from these data sets. The 3D reconstructions obtained will allow the student to obtain quantitative data that can be further analyzed. The data obtained strongly suggests some issues with the neural circuitry of the hypoglossal due to the smaller neuronal sizes, which may potentially be a factor in developmental dysphagia. Another striking discovery is that the standard deviation of the mean volumetric value of the neurons increases in LgDel animals (i.e., variability). Finally, we found that some of the hypoglossal neurons show alterations in their dendritic branching and some show misdirected axons. Both morphological parameters support the signal processing and integrative function of hypoglossal motor neurons, but we will need to analyze 40-60 more cells in order to validate the initial finding and to build reliable population data.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Open Access

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Comments

To be presented at GW Annual Research Days 2017.

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3D Morphological Analysis of Neurons in Hypoglossal Nucleus in Mouse Model of DiGeorge Syndrome

Pediatric dysphagia is a condition characterized by difficulties in feeding and swallowing in infants and children. The tongue is one of the structures involved in feeding and swallowing, and abnormalities in tongue control occur in patients suffering from dysphagia. Cranial nerve XII, hypoglossal nerve, is a nerve that originates from the hypoglossal nucleus in the brain stem and innervates the tongue; it is responsible for proper functionality of the tongue. DiGeorge Syndrome feeding and swallowing abnormalities occur in the early developmental stages of the disease. The goal of this research is to further identify morphological differences of neurons within the hypoglossal nucleus. These anatomical and physiological differences will be observed in wild type mice (WT) and in mice with a large deletion of genes (LgDel) that is equivalent to 22q11DS (the gene deletion causing DiGeorge Syndrome) in humans. These differences will be studied by evaluating parameters, such as volume and quantity of neurons in the hypoglossal nucleus. As well as, the dendritic lengths, sizes, and branching points will be analyzed as well the volume of individual neurons in the hypoglossal nucleus – which have undergone electrophysiological measurements and parameters

Utilizing confocal and fluorescence microscopy techniques with the ZEISS 710 confocal instrument, the student acquires 3D data sets that can be further analyzed. The images will then be observed to identify qualitative differences of the cells. Next, the images will be analyzed utilizing Imaris because Imaris contains options that allows users to import these image sets and reconstruct 3D structures from these data sets. The 3D reconstructions obtained will allow the student to obtain quantitative data that can be further analyzed. The data obtained strongly suggests some issues with the neural circuitry of the hypoglossal due to the smaller neuronal sizes, which may potentially be a factor in developmental dysphagia. Another striking discovery is that the standard deviation of the mean volumetric value of the neurons increases in LgDel animals (i.e., variability). Finally, we found that some of the hypoglossal neurons show alterations in their dendritic branching and some show misdirected axons. Both morphological parameters support the signal processing and integrative function of hypoglossal motor neurons, but we will need to analyze 40-60 more cells in order to validate the initial finding and to build reliable population data.