BonBon

Hey y'all,
Do people normally reach out to the admission office after the rejection? I want to know what my weaknesses are and how to improve, hoping I can prepare a better application for the following year. If so, what is the best way to reach out?

No problem I should add: a general ranking/prestige may not be reflected on your specific field of interest. For example, let's say you're interested in neurodegeneration.  A "lower ranked" school may have an entire center dedicated to neurodegenerative diseases and have a strong connection with a great nearby hospital, while a higher ranked school may put less emphasis on that topic of interest. Something to consider.

Same here...applied to 12 programs..received 4 rejections and no interviews yet. Really wondering if there's any hope at this point? Especially regarding waitlists and how they work.

I would dress in business attire: blazer + blouse/shirt and tie. Interviews are not very formal but it can't hurt to dress professionally.
How to stand out: show your personality and passion for science! Interviews can range from you talking about your work for 20 minutes straight to very casual conversations about science and doing research. Interviewers want to see that you will complete a PhD. That means showing that you love science, showing you are not blindly following the instructions of a superior, and frankly that you can handle the workload. If you haven't done an independent project, be prepared to justify how you will be able to work on your own/without guidance. You will probably also be asked if you could continue working on your current project for 1 more year, what you would do.
Also, there will be a portion where the interviewers tell you about their work. Look interested and ask questions. I read a couple papers of each of my interviewers before going in. I don't think it was necessary but did help me.
Finally, you will be asked pretty often what you want to do in grad school. It doesn't have to be specific, but dream big. It would help to know a couple of techniques you're interested in learning and the subfield you want to explore. Example: "I'm really interested in addiction and drug use and would love to learn some molecular techniques to study opioid receptors as well as do fMRI studies in patients..." etc. It doesn't have to be perfect.
Overall, schools are also adjusting to online interviews and recognize the challenge. They are also trying to convince you to go to their school, so they are also working very hard to show the culture and value of their program. If you have multiple interviews lined up, you should also be feeling out the school and seeing how well you connect with the program! I also get nervous about online meetings but it's a two way street - everyone is very understanding of that and some difficulties are expected. 
In short: 
-practice talking about your research clearly and concisely
-know who you're interviewing with
-say a bit about what you dream of doing in grad school
-relax, you'll do fine if you like science
-take note of how much you like the school
Hope that helps, feel free to reach out to me if you have any other questions.
 

I'm gonna provide a different perspective here and say that it's totally fine if you completely switch your subfield during grad school. I also have a cell & molec background and am interested in systems/computational stuff. I've talked to many computational professors and none care what your background is, as long as you're interested in the work. Some even find it to be a positive that I've had a different background.
What DOES matter for getting into grad school is how you talk about your research, i.e. why did you form your hypotheses? why did you choose your techniques? how did you interpret your data? The point is, don't feel like you have to change labs, unless you're tortured by the work you do now. If you had one more year in your current lab, would you have significantly more to talk about? Adjusting to a new project can be tough and may not give you as much to talk about in next round of applications as seeing your current project to completion. 
Ultimately I can't tell you what to do, but don't feel discourage from pursuing computation in grad school if you weren't already in computation! It frankly doesn't matter as long as you can back up your interest. 
good luck, you seem qualified and sure of yourself, so you'll be fine in the end.

Do you have computational backgrounds? If not, programs like neuromatch specifically train you on comp neuro skills so I’d recommend that over the summer. Some other summer schools also help a lot! 
 
Since you are already at Harvard, you should definitely reach out to some professors there to ask if you could do research w them as an intern. Feel free to message me for specific professors in comp neuro, but they are  also not hard to figure out from their websites. I’d also look at other schools and professors whose websites will say that they are looking for summer interns or just “undergrads/masters” to work with. Even if not, just reach out as long as you are interested in their papers - you have nothing to lose.
 
My field is comp neuro (and I’m also an international student from China!), and this field is still quite small and definitely needs more talent. So it’s great that you want to research in this area!

This is super helpful! Thanks a million!!!?

Honestly, at least you know you like research! You sound incredibly ready for PhD, so it must be just research area doesn’t quite match up. I know comp Neuro is especially hard to match with (you need practical experience with coding skill and neuro modeling/imaging).
 
I’m sorry the projects you are working on don’t line up with what you want to do, but given your experience I’m sure transferring or applying to another lab would be a lot easier for you than most, especially since you’re in neurobio already. What helped me was being pointed to several email lists in research areas that I like, and searching for lab research positions in research I was interested in.  Also reaching out to labs you like and asking if they have any research positions available. Worst case scenario you can leave them with your CV and if a position opens they will be more likely to contact you.
You’re in a better boat than me, I’d say, but I hope this helps! 

I'm so sorry to say, but odds are you won't hear invites from most of them, as these programs usually send invites in one go and not in batches. There's a chance with waitlist, but if you see invites being sent out its best to try moving on if you didn't get one. Dwelling on potentially being on the waitlist does more harm than good :/.

What's your profile like? More often than not it comes down to fit and research experience, both of which can be remedied by seeking a research assistant / lab manager position at a top 50 program. Which isn't easy, and takes time, but once you find one you can be financially stable while spending time building your skills and CV, refining your research interests, and reaching out to prospective  labs. Being able to attend conferences and present is a huge way to make connections, too. 

Initially being rejected my first round, I was really disappointed. One of the labs I applied to, though, liked me enough that they helped me find a job as a Lab Manager. Its not what I originally wanted, but it ended being incredibly worth it. Now, even if I'm rejected again, I'll just apply next year knowing I'll have a stronger CV, more publications, more connections, etc. 

Point is, you have got options to pursue, just don't give up!