In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Q: Sentence1: Matt studied brain chemistry for his PhD. Sentence2: He was particularly interested in the prefrontal cortex. Sentence3: In his work, he hopes to improve understanding on our emotions. Sentence4: Right now, he is studying the link between fear and aggression. Sentence5: He hopes this can improve the treatment of army veterans.
A:
Matt