Here's an idea I've been toying with. What would happen if you fed an electrical signal, say a certain radio frequency, directly into the brain? Obviously, the signal's power would be adapted so as not to cause damage. Would the brain develop a sensitivity for that particular type of signal? Something like a new sense, probably based on the amplitude of the signal in question, so the closer you get to the source, the more powerful the sensation. An external sensory apparatus, such as an antenna, would most likely be required. It'd probably look quite silly, too. Does anyone know of any experiments of this sort having been done? The brain-machine interfaces I've read about focus either on controlling artificial limbs, or restoring sight or hearing. Another question, roughly in the same area. How much could someone's perception of time, in the sense of frames per second, be enhanced(i.e., brought closer to that of an insect, or a bird) just by modifying visual stimuli accordingly(i.e. incrementally increasing the speed with which an image is changed)? Is there a hardware limit, something related to the size of the brain and the distance a signal has to travel?