Ramez Naam wrote two Sci-Fi novels on that issue: Nexus and Crux. Drinking a silvery liquid of communicative nanobots is enough. The bots autonomously find their way into the brain and connect to neural cells.

Regarding non-invasiveness this vision might get acceptance. Unsolved technical issues are: building such nano bots, supplying energy and dynamic long range communication. I fully agree with Bostrums scepticism.

Low social acceptance of Google glass shows that humans with brain interconnection might face similar repercussions. Via BCI you could 'videotape' what you see with your eyes. A BCI will probably not be so easy deactivated than switching off your Google glass.