In rodents, the dorsolateral part of striatum, receiving synaptic inputs from the primary motor cortex, contributes to controlling voluntary movements as a part of the skeletomotor loop. Most of striatal neurons are medium spiny neurons (projection neurons) which receive glutamatergic inputs from the cerebral cortex and send GABAergic outputs to other parts of the basal ganglia. The striatal projection neurons participate in either the direct pathway (expressing dopamine D1 receptors) or the indirect pathway (D2 receptors) exclusively. The D1- and D2-expressing neurons should be excited and inhibited, respectively, by dopamine release from the substantia nigra neurons encoding a reward prediction error. So far, people have believed that the activation of direct pathway results in an enhancement of voluntary movements (like as an accelerator for automobile), while the activation of the indirect pathway results in a depression of them (a brake). However, it remains unknown how individual striatal neurons for the two pathways represent motor information, and whether their motor information is modulated by reward expectation. Recently, we juxtacellularly examined the activity of single dorsolateral striatal neurons in the rats performing voluntary forelimb movements in a reward-expectable condition. The two-pathway system may work, not just antagonistically, but rather coordinately by functional activations of individual striatal neurons to integrate motor and reward information.