<p>Whether or not you can do a dual-degree in those fields depends on how any given school structures its programs or departments in those fields.</p>
<p>Some neuroscience programs are offered as a track within a general biology major. If that case, you take the courses required of all biology majors as well as the required courses for that track; it’s not a dual major, however. Usually, you are not permitted to complete two different tracks within a general biology major.</p>
<p>Some neuroscience programs are offered as an interdisciplinary certificate open to majors from participating departments, usually biology or psychology. In that case, you would major in biology and also complete the required coursework for the certificate. Certificate programs are in an addition to your major; they may or may not be considered a minor.</p>
<p>Some neuroscience programs are offered as an interdisciplinary nondepartmental major. In this case, you would complete the requirements of the major itself. In this case, you would not be required to complete a departmental major in a traditional discipline, e.g., biology, psychology. Depending on the school, you usually would be allowed to complete another major in a related field, or even in an unrelated field. </p>
<p>Some neuroscience majors are offered as a departmental major in a standalone neuroscience dept. In that case, you might or you might not be allowed to complete another major in a biology, depending on the school. The issue here isn’t whether you are permitted to do dual majors, but whether you are permitted to do dual majors in two different bioscience departments.</p>
<p>This about covers the different possibilities for how these programs are structured. Of course, different schools name and divide up their biology dept(s) in different ways. So, depending on the particular school, you might have a biology dept. or a zoology dept or an ecology & evolutionary biology dept or an organismic & ecological biology dept, and so on. The point is that the neuroscience major and courses might be located in different depts in different schools, so you have to look for depts with various names, not just “biology”.</p>
<p>I think most schools permit dual majors, and it is the student’s choice, but you usually would have to complete all the requirements for both majors (i.e., most schools don’t allow courses in one major to also do double duty as courses for the other major). This has some potential disadvantages, including limiting the number of electives you can take in other areas of interest, focusing you too much on two closely related fields, sacrificing breath for depth, difficulty completing both majors within a four-year time frame, etc. There also are some schools that do not allow dual majors, e.g., Princeton, or that only permit major + minor combinations.</p>
<p>At the undergrad level, you apply for admission to a school, not to a department. Once admitted, certain departments or majors might have additional requirements for declaring that major, but usually it just involves completion of pre-requisite courses with a certain GPA.</p>