Investigation of the connectivity between the deep cerebellum and thalamic system using trans-synaptic tracers

• Main Author: Heng, Deanna Li-Ying
• Other Authors: Albert I. Chen
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Science::Biological sciences
• Online Access: http://hdl.handle.net/10356/63950
• Institution: Nanyang Technological University

The deep cerebellar nuclei (DCN) play a crucial role in fine tuning motor behaviour and motor learning by integrating input from pre-cerebellar nuclei and cerebellar cortex and relaying this information to higher regions of the brain. While conventional lesion studies have demonstrated the DCN’s association with motor functions, no known recent tracer study has been able to define its neural connectivity, the nature of the complex motor pathways and specific efferent targets. As studies have revealed the importance of the thalamic system in sensory and motor functions, we sought to investigate the nature of the circuitry between the ventral posterolateral thalamic nucleus, a region associated with the motor thalamus, and the DCN. In this experiment, in vivo stereotaxic injection of wheat germ agglutinin, a trans-synaptic tracer, was carried out at the left hemispheric ventral posterolateral thalamic nucleus. Immunohistochemical techniques revealed the presence of immunoreactive positive signals neurons of the contra- and ipsilateral medial DCN, lateral DCN, superior vestibular nuclei and contralateral spinal trigeminal nucleus. Our findings provide a better understanding of brain connectivity and lay important groundwork for our plans to analyse the behaviours of mice by light activating subpopulations of neurons in the mouse cerebellum.