When a human and an intelligent machine work together as a team, human trust can influence performance. Yet, an electrophysiological signature of trust has not been isolated. In order to isolate such a signature, the research team recorded fMRI or event-related potentials while subjects were playing two cognitive games. At the first experiment, human subjects played a theory-of-mind bilateral game with two types of computerized agents: with or without humanlike cues. At the second experiment, human subjects played a unilateral game in which the human subjects played the role of the Coach (or supervisor) while a computer agent played as the Player. Electrophysiological activities in brain regions belonging to the theory-of-mind network correlated with perceived capability, especially when a machine opponent had some human-likeness. In particular, the research shows that activity in the left parietal region correlating with a human players future behavior can be identified as the neural signature of capability-based trust. These results reveal that brain signals underlying trust as influenced by perceived capability and human-likeness might be useful for performance optimization of human-machine systems.