nervous system & electronic media
Norman Doidge (channeling McLuhan):
Electronic media are so effective at altering the nervous system because they both work in similar ways and are basically compatible and thus easily linked. Both involve instantaneous transmission of electronic signals to make linkages. Because our nervous system is plastic, it can take advantage of this compatibility and merge with the electronic media, making a single, larger system. Indeed, it is the nature of such systems to merge whether they are biological or man-made. The nervous system is an internal medium, communicating messages from one area of the body to another, and it evolved to do, for multicelled organisms such as ourselves, what the electronic media do for humanity — connect disparate parts.