Symbiotic goes both ways. One entity “communicates” with the other and at the same time receives “communication” from the other.
I already pointed out the variety of technologies that are available, with many more to come, to extract data from a living entity and transmitting them to another (machine) entity. The problem of input/output for a machine is well understood, since machine are basically a connection between input and output, they are designed with this in mind. Living being have evolved over millennia also to become available to make sense, and use of a variety of inputs and to generate outputs. However, they have not been “designed”. We need to work with living beings just accepting the way they are, we need to conform to the way they accept input and what those inputs “mean” to them. Their internal communications is often compared to the internal communication of a machine, we speak of electrical signals, as an example, to activate muscles, to convey the sensorial information… Actually, it is an electrical communications but it is not based on electrons, as in our computer circuits, but on protons and this leads to some significant differences. Electrons spread around ad if we were to use electrons to activate nerves controlling a muscle they would spread around all nerve fiber leading to an uncontrolled contraction. What happens in the living being is an activation via ions, protons, that are selectively captured by the cell membrane, thus resulting in a strict control of communications. Protonics, then, not electronics is the underpinning of communications with a living being.
Optogenetics is another technological area that has progressed significantly in the last 10 years. More progress are required in the conditioning of the neurons, in conveying the activating light to the right area in the brain, in understanding the correlation among various brain areas so that stimuli can be directed to the appropriate neural circuits, and so on.
Experiments have shown that transcranial electrical stimulation can affect the capability of the brain to focus attention, to increase its capability in performing certain tasks. However we are still at the very beginning of this journey and we, for one, do not know what could be the side effect of transcranial stimulation.
Ethical issues are very strong (as they are in optogenetics). Basically any time we fiddle with living being altering their potential behavior we run into ethical issues.
This issue with symbiotic machine should be considered from the start.