Luca Liebi

Project Summary: Movement requires neuronal circuits to integrate incoming signals and generate output commands. The motor superior colliculus, an evolutionarily conserved midbrain structure, receives extensive inputs from higher-order motor centers and harbors neurons projecting to the caudal brainstem. This unique connectivity places the motor superior colliculus in a privileged position at the forebrain-brainstem interface. However, the specific functions of this brain region and how it integrates synaptic inputs to regulate movement remain elusive.

Through this project, we demonstrated that a genetically defined subpopulation of collicular neurons projecting to medullary areas is essential for action selection and movement execution in a skilled motor task. Additionally, anatomical and functional evidence suggested that this population of neurons in the motor superior colliculus may play a crucial role in integrating converging inputs from upstream motor structures. To facilitate mechanistic studies of input integration, we developed and validated a dual-color patterned optogenetic stimulation system, enabling independent and simultaneous activation of distinct afferent populations while performing whole-cell in-vitro recordings. 

Collectively, our work underscored the central role of the superior colliculus in motor control and laid the foundation for deeper insights into the mechanisms underlying neuronal integration at the forebrain-brainstem interface.