This week, Matt Damon returns to the big screen as Jason Bourne, a secret agent who has forgotten his entire life and is piecing it back together while confronting political and economic conflicts. We wondered how realistically the series depicts brain science.

The core premise behind the series – which now includes 13 books and 5 movies – is that it's possible for a traumatic event, like being shot, to cause someone to forget everything about their past, yet still retain all their skills and abilities. For example, Bourne still remembers how to fight with martial arts, use weapons and speak different languages.

We asked Michael Drew, a professor of neuroscience at the University of Texas at Austin, could that really happen?

"Jason Bourne actually has some things in common with the most famous patient in the history of neuroscience, known as H.M., a man who was having terrible seizures in the late 1950s," says Drew.

H.M.'s doctors decided to remove a part of his brain called the hippocampus that was thought to be the source of the seizures. What the doctor didn't know, but which we now do, is that the hippocampus plays a critical role in learning and memory. The surgery did stop H.M.'s seizures, but it also erased all of his past memories for experiences and events, what scientists call episodic memories. That part sounds a lot like the fictional Jason Bourne.

The real life H.M. did retain his full command of the English language and retained much of his factual knowledge. So too, did Jason Bourne. These kinds of memory—called procedural and semantic memory—rely, to a large extent, on different parts of the brain than episodic memory. So, despite not remembering past experiences, Jason Bourne could still recall how to fight with martial arts, use weapons and speak other languages.

"There are other examples of people who have experienced concussions or other kinds of trauma who lose a particular kind of memory, but not others," says Drew. "So that seems at least plausible."

But Drew pointed out that there are some key differences between H.M. and the fictional Jason Bourne. For example, H.M. lived in a kind of eerie limbo in which each time he saw a scientist whom he'd interacted with before, he could not remember them, even after the hundredth time. In other words, H.M. couldn't form new episodic memories.

Fortunately for Jason Bourne, he could form new episodic and procedural memories. Without that ability, the Bourne books and movies would be pretty dull.