I haven't shared any neuroimaging data as of yet, but I want to make sure I understand the rules before I do. This is probably a very easy question, but how does data sharing work with already acquired data?
Poline et al. (2012) says:
Many informed consent documents do not mention the possibility of broad data sharing, thereby posing a major barrier, as it is uncommon for IRBs to grant the researcher the right to pub- licly distribute the data if written consent for such release wasn’t requested in the original submission. In such cases, researchers wishing to share retrospective data might be permitted to do so if they were able to obtain new written informed consent for data sharing, a daunting task which for many research labs would be time-consuming and often fruitless. Further, some IRB/ERBs simply have not been willing to approve protocols that request open data sharing (Al Grudzsinksas, personal communication).
On the other hand, Gorgolewski & Poldrack (2016) say:
Even though in the United States deidentified data can be freely shared without specific participant consent, the rules differ in other countries (and they may change in the upcoming revisions to the Common Rule, which governs research in the US). In addition, it is only fair to inform your participants about your intention to maximize their generous gift by sharing their data, and to allow them to withdraw from research if they don’t wish to have their data shared.
Obviously if data sharing wasn't mentioned in the original consent forms, it is best to obtain new consent from the subjects. However, in cases where obtaining updated consent is infeasible, which is correct? Can the deidentified data be shared?