Answer:his hippocampus
Explanation:The hippocampus is a is crucial part of the brain that helps us form new memories and also learn new things and it also plays part in emotions. It pays a major role in organization ,formation and storage of these new memories and being able to relates these memories to certain emotions .
In order to recall the route to his doctor's office Mateo would have needed to form,organize and store this route as a new memory but his inability to do so indicates that his hippocampus has been damaged; which is responsible for this.