Motor control

Algorithm

Neuroscience

Biology

Premotor cortex

Stimulation

Computer science

Primary motor cortex

Dopamine

Forelimb

Projection (relational algebra)

Pyramidal tracts

Anatomy

Striatum

Cerebral cortex

Dorsum

Motor cortex

Science Advances

The interaction of descending neocortical outputs and subcortical premotor circuits is critical for shaping skilled movements. Two broad classes of motor cortical output projection neurons provide input to many subcortical motor areas: pyramidal tract (PT) neurons, which project throughout the neuraxis, and intratelencephalic (IT) neurons, which project within the cortex and subcortical striatum. It is unclear whether these classes are functionally in series or whether each class carries distinct components of descending motor control signals. Here, we combine large-scale neural recordings across all layers of motor cortex with cell type-specific perturbations to study cortically dependent mouse motor behaviors: kinematically variable manipulation of a joystick and a kinematically precise reach-to-grasp. We find that striatum-projecting IT neuron activity preferentially represents amplitude, whereas pons-projecting PT neurons preferentially represent the variable direction of forelimb movements. Thus, separable components of descending motor cortical commands are distributed across motor cortical projection cell classes.

Motor cortical output for skilled forelimb movement is selectively distributed across projection neuron classes