We trigger actions in response to external sensory cues, like pushing the gas pedal when the lights turn green. This cue-triggered action is often spared in Parkinson’s patients, implying that distinct neuronal substrates mediate cue- and self-triggered actions. We discovered ascending mesencephalic locomotor region (MLR) neurons projecting to motor thalamus is necessary for cue-triggered licking in mice. Similar to sensory cues, stimulation of these neurons switches activity in premotor cortex to trigger licking. We propose MLR – thalamus – premotor cortex pathway converts motor-planning into actions.