Implants in the human brain can be called primitive when considered in light of the organ they are meant to interface with. While the state of the art in technology uses minute electrical impulses to communicate with groups of neurons within the brain, the brain itself goes far beyond mere patterns of electrical impulses. Modern science has confirmed the existence of several score of neurotransmitters, and there are probably more that haven’t been identified yet. I’m willing to bet that there are other mechanisms underlying the operation of the brain that I don’t even know about because I’m not a neuroscientist. However, scientists far more erudite than I at Linköping University in Sweden and the Karolinska Institutet think that they’re on their way to developing artificial neurons which can communicate with organic nerve and brain cells using neurotransmitters rather than electrical impulses. They’ve developed a new plastic that releases certain neurotransmitters under certain conditions, and thus can communicate with selected synaptic groups at a time and not large swaths of neurons (which can cause misfires and thus what amounts to transmission noise within the brain) due to the selective nature of brain cells. In the next issue of the journal Nature Materials results of experiments in controlling the auditory cortices of guinea pigs with these new materials will be published.
The first logical step, I think, would be to improve the current generation of cochlear implants to correct certain forms of deafness, which are already fairly advanced. Cochlear implants are a well known technology and while they’re not exactly common they do see use. It wouldn’t surprise me if later versions of this technology were used to improve optical prosthetics, which are very limited in resolution and capability right now.
From there... who knows?