Anatomical Tracing of the Efferent and Afferent Projections of the Red Nuclues

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University of Calgary
Motor behaviors are essential for survival, such as walking, foraging for food or escaping predators. Still, little is known about the specific descending pathways to the spinal cord that control complex motor movements. From the brain, there are four main pathways that descend directly to the spinal cord which contribute to the wide array of movements used in our daily lives. One of these pathways is the rubrospinal tract, which originates at the red nucleus in the midbrain. Previous experiments revealed that the red nucleus is important in the fine motor control, response rate and smoothening of limb movements. Despite the importance of the rubrospinal tract and the red nucleus, this pathway has not been studied extensively in mice. This project aims to determine the afferent and efferent connectivity of the red nucleus. This was achieved using viral tracing techniques. The retrograde tracer cholera toxin B (CTB) and the anterograde tracer biotin dextran amine (BDA) were injected into the red nucleus and their resulting expression throughout the brain was identified. Based on preliminary data, the major areas that project to the red nucleus are the primary and secondary motor cortices, the preoptic area, the posterior lateral hypothalamus, zona incerta, periaqueductal grey and the gigantoreticular nucleus. The results of this study provide the fundamentals for future studies of the rubrospinal tract. Moving forward, the cell types and role of these identified pathways can be studied to further build on our understanding of motor pathways.
Red nucleus, projections, retrograde tracing, anterograde tracing, rubrospinal tract
Ngan, S., Sharma, S., & Whelan, P. J. (2018). Anatomical Tracing of the Efferent and Afferent Projections of the Red Nuclues (Rep.). Calgary, AB: University of Calgary.