Using viral tracing methods to identify connectivity deficits between cerebellum and the thalamus in the Ts65Dn mouse model of Down Syndrome
FNU Mir Abbas Raza
I.Objective: Down Syndrome (DS) is a genetic disorder characterized by behavioral abnormalities in multiple brain regions. The cerebellum, a key area of the brain responsible for governing motor coordination and motor learning, has been implicated as being affected in many different Neurodevelopmental Disorders (NDDs), including DS. The cerebellum forms an extensive network of connections with other brain regions during development - also known as the ‘cerebellar connectome’. If there is dysfunction in the cerebellum during critical periods of circuit formation, it could result in altered development and dysfunction of extracerebellar targets such as the thalamus. Therefore, it is crucial to examine the development of the cerebellar connectome in the context of complex disorders like DS. However, the connections between the cerebellum and other brain regions have not been systematically mapped out across postnatal development. Most importantly, potential disruption in these connections has not been mapped out at the synaptic level in DS. Our goal is to determine the connectivity between the cerebellum and one of its major targets - the thalamus across postnatal development and how this connectivity is potentially disrupted in a mouse model of DS.II.Methods: To visualize connections between the cerebellum and the thalamus, we will use a precise and efficient Cre-dependent viral tracing strategy. This will enable us to specifically target the cells in the cerebellar nuclei that project to the thalamus. To accomplish this, Cre-expressing promoter specific Adeno Associated Viral vectors along with Cre-dependent viral vector carrying the Double-floxed inverse open reading frame (DIO) system and Green Fluorescent Protein (GFP) reporter gene will be injected into the cerebellar nuclei of the DS mouse model. This system will control the timing and specificity of gene expression, enabling the labeling of only the cells that have been infected with both viruses. The GFP reporter gene will allow for the visualization of the labeled cells and their projections. Histological analyses will be performed to visualize the GFP-labeled cells and their projections in thalamic nuclei. High-resolution images of the labeled cells and their projections will be obtained using confocal microscopy. The morphology of the labeled cells, including their dendritic and axonal arborization, as well as their connectivity patterns, will be analyzed using ImageJ and MATLAB.III.Significance: Although the prevalence of DS is on the rise, there has been little improvement in the development of innovative therapies to enhance behavioral outcomes for children with DS in recent times. One of the contributing factors to this lack of progress is the inadequate basic research on the neural connection deficits in the DS brain. The proposed study will help provide crucial data in understanding atypical brain development in DS, specifically, alterations in neural circuitry. Mapping connections between the cerebellum and the thalamus and studying the deficits in these connections during development in the Ts65Dn mouse brain will allow us to understand more deeply the underlying mechanism of dysfunction related to these regions and provide avenues to eventually develop targeted interventions towards treating deficits in children with DS.
Primary Advisor's Department
Stander Symposium, College of Arts and Sciences
Institutional Learning Goals
Scholarship; Scholarship; Scholarship
"Using viral tracing methods to identify connectivity deficits between cerebellum and the thalamus in the Ts65Dn mouse model of Down Syndrome" (2023). Stander Symposium Projects. 3241.
Presentation: 1:40-2:00 p.m., Science Center 146