This paper is an excellent starting point http://www.columbia.edu/cu/biology/pdf-files/faculty/Yuste/yuste%20et%20al.nature2017.pdf.
Additionally, this year there has been a lot of work from IEEE trying to push for a standard which deals with many ethical aspects of the technology: https://standards.ieee.org/content/dam/ieee-standards/standards/web/documents/presentations/ieee-neurotech-for-bmi-standards-roadmap.pdf.
You should check the work of Ricardo Chavarriaga which has produced a lot of awesome research around these topics.