Between thoughts and actions: motivationally salient cues invigorate mental action in the human brain.

The maintenance of goal-directed behavior relies upon a cascade of covert mental actions including motor imagery and planning. Here we investigated how cues imbued with motivational salience can invigorate motor imagery networks preceding action. We adapted the Pavlovian-to-instrumental (PIT) paradigm to explore this by substituting motor action with motor imagery. Thus, reward was contingent upon a given level of imagery-induced neural activity using real-time fMRI. We found that the concomitant presentation of reward-related cues during motor imagery not only enhanced neural responses in motivational centers (ventral striatum and extended amygdala) but also exerted a motivational effect in the imagery network itself. Moreover, functional connectivity between ventral striatum (but not extended amygdala) and motor cortex was heightened during imagery in the presence of the reward-related cue. The concurrent activation of "value" and "action" networks may illuminate the neural process that links motivational cues to desires and urges to obtain goals.