Processing of limb kinematics in the interpositus nucleus

Neural representations of limb movement kinematic parameters are commonamong central nervous system structures involved in motor control, such as theinterpositus nucleus of the cerebellum. Much experimental evidence indicatesthat neurons in the interpositus may encode limb kinematic parameters bothduring active, voluntary actions and during limb motion imposed passively,which entrains only sensory afferents. With respect to the sensory processingof information related to movement kinematics, we show that interpositusneuronal activity can parse out the directional from the scalar component (i.e.,the movement speed) of the velocity vector. Moreover, a differential role for theanterior and posterior portion of interpositus in encoding these parametersemerged from these data, since the activity of the posterior interpositus wasspecifically associated to changes of movement speed. Limb movementrepresentations in the interpositus nucleus may be instrumental for the controlof goal-directed movements such as shaping hand during grasping or precisefoot placement during gait. Finally, we discuss the idea that sensory informationabout the movement kinematics contribute to both feedback and anticipatoryprocesses for limb movement control.