Basically, there are some majors that you have to be admitted to after completing some prereqs and applying to the major. One of these majors is neurobiology.
"Once you are admitted to the University of Washington majors at the UW fall into three categories.
1. Open Admission: May be declared at any time
2. Minimum Admission Requirements: Require certain prerequisites and/or a minimum GPA.
3. Competitive Admission: Require any of the following; Specific GPA, test scores, personal statement, relevant experience, writing sample, recommendations, portfolio, and/or separate applications."
Minimum Admission isn't really a big deal; it's just stuff you do anyways in the process of doing the major (Bio, for example, requires you to do some intro bio courses with a min GPA of 2.5 or something, which is easy to get).
Competitive Admission is where a major has a lot of prereqs, and usually people apply at the end of sophomore year for these types of majors, though it really varies. Neurobiology is one of these majors.
UW Undergraduate Neurobiology Major
Anyways, what you should get out of this is that: 1) Whatever you declare as your major on your UW application doesn't matter, 2) Your performance in courses at UW will determine your acceptance into competitive majors such as neurobiology.