For Post-Doctor's petition in EB-1A, an USCIS adjudicator often indicates that the publications are expected for Post-Doctors, therefore not the claimed accomplishments, or not evidence of extraordinary ability or outstanding ability. 

Similarly, an USCIS adjudicator may also minimize the applicant's value of citations as a necessary part of the publications criterion. The USCIS adjudicator may also dismisses the applicant's collaborative research work as not the individual accomplishments.

Therefore, in your RFE response, you need to prove your own contributions in the collaborative work, and also prove that your publication and citation records are above your colleagues in your field, and they are indeed the evidence of your extraordinary ability.