Advances in neurotechnologies, artificial intelligence (AI) and Big Data analytics are allowing interpretation of patterns from brain data to identify and even predict and manipulate mental states. Furthermore, there are avenues through which brain data can move into the consumer sphere, be reidentified and brokered. In response to these developments, there have been a number of approaches proposed to strengthen protections of brain data. To better understand the landscape of brain data protection discussions, we conducted a scoping review to identify (...) the rationales for establishing brain data protections and the proposals for protecting brain data offered in the ethics and neuroscience literature. To draw comparisons, we also surveyed the rationales given in the literature for the protection of sensitive behavioral inferences drawn from other types of personal data and associated approaches to achieving protection. This systematic examination of the rationale behind heightened protection for brain data should be useful to clarify the functional and conceptual bases given for brain data protection and to provide a better grounding for evaluating how the different approaches to brain data protection address these concerns. (shrink)