Nature, Vol.508, No.7496, 351-351, 2014
Brainstem nucleus MdV mediates skilled forelimb motor tasks
Keywords:Translating the behavioural output of the nervous system into movement involves interaction between brain and spinal;cord. The brainstem provides an essential bridge between the two structures;but circuit-level organization and function;of this intermediary system remain poorly understood. Here we use intersectional virus tracing and genetic strategies in;mice to reveal a selective synaptic connectivity matrix between brainstem substructures and functionally distinct spinal;motor neurons that regulate limb movement. The brainstem nucleus medullary reticular formation ventral part (MdV);stands out as specifically targeting subpopulations of forelimb-innervating motor neurons. Its glutamatergic premotor;neurons receive synaptic input from key upper motor centres and are recruited during motor tasks. Selective neuronal;ablation or silencing experiments reveal that MdV is critically important specifically for skilled motor behaviour;including;accelerating rotarod and single-food-pellet reaching tasks. Our results indicate that distinct premotor brainstem;nuclei access spinal subcircuits to mediate task-specific aspects of motor programs.