The role of the cerebellothalamocortical pathway in skilled reaching

The cerebellothalamocortical pathway has been implicated in a broad array of motor functions ranging from controlling the timing of movements to motor adaptation. There is a considerable gap in knowledge concerning how the cerebellum influences cortical control of the upper limbs via the motor (ventrolateral) thalamus. Despite its position as the direct influencer of cortical activity, the cerebellar motor thalamus has been understudied, likely due to technical difficulties in reliably identifying and recording from this area in awake, behaving primates. Scarcely any work has examined the relationship between the motor thalamus and either the cerebellar output nuclei or the motor cortex. This nucleus is involved in different aspects of motor control, but it is not yet clear how cerebellar signaling is transformed at the level of the thalamus, or how thalamic activity modifies or sustains aspects of cortical activity. My thesis aims to clarify the nature of cerebellar influence on cortical control of movement in primates by investigating functional and trial-by-trial relationships between the primary motor cortex and cerebellar motor thalamus. My thesis focuses on multiple outstanding questions in neural basis of motor control: Does input the cerebellar thalamus to M1 drive movement initiation– or the switch between motor preparation to execution? Do M1 units receiving cerebellar input via the thalamus have a distinct functional role relative to the rest of the M1 network? A combination of simultaneous cortical and thalamic population recordings during reaching, electrical stimulation identification, statistical modeling, and simulation-based validation approaches are used to support our answers to these questions.