Cognitive-Motor Duality in Human M1 and Cerebellum

The translation of abstract cognitive intention into localised physical action is a defining feature of voluntary behaviour1,2. To achieve this, the brain must maintain a highly regulated preparatory state, yet the macroscopic architecture of this interface remains elusive. Historically, the primary motor cortex has been viewed simply as a strictly contralateral kinematic relay3, making its robust bilateral activation during single-limb preparation a long-standing functional paradox4,5. Here, we show that human motor preparation is driven by two distinct, superimposed neural processes operating across the cerebral cortex and cerebellum. By mathematically decomposing neuroimaging signals from over six thousand sessions, we identified a broadly distributed cognitive readiness network that dictates the precise timing of an action, and an independent, highly localised kinematic preparation network that controls execution speed. This macroscopic duality maps human whole-brain dynamics onto the neural subspaces and circuits previously observed only at the microscopic level in animal models6-9. Furthermore, we reveal that genetic risk for Parkinson’s disease selectively impairs this cognitive readiness network during healthy adolescence. Ultimately, these findings redefine the cortico-cerebellar axis as an active computational interface integrating abstract thought with physical embodiment, offering a generalisable framework for understanding mind-body synchronisation and early neurodegenerative vulnerability.