Kira Rienecker | 17 MAY 2016
How much of a human do you need to replace to create a cyborg? How far can you go before a cyborg becomes a biological computer? Does Inspector Gadget from the 1983 TV series still retain the autonomy, dignity, and essential rights he had before becoming a cyborg?
Some of the common characteristics that define science fiction cyborg include mechanical limbs, enhanced senses, and computer interfaces linked directly to the consciousness. At the present, we are getting better at making robotic limbs to replace lost arms and legs, but what if we could distribute an electrical system throughout the brain and make that SciFi step? This paper suggests a graphene based neural interface might get us closer to electronic neural prostheses. Graphene, which has very interesting properties we will not go into here, but which make it a material with promise for building neuro-interfaces.
Neuro-interfaces are systems that allow us to send signals (usually electrical) to neurons or brain tissue. Think of it as a very basic computer output into a cyborg brain, allowing an external computer to control programs. If we send signals to neurons to fire or to repress firing, we can hijack the basic “what fires together, wires together” mechanism of synaptic pruning. Consequently, an extended neuro-interface could tell brain regions when to be active or silent, and even coordinate multiple regions.
But how would we distribute such an electrical system throughout the brain? While the particular graphene-based interface described in the paper had the advantage of being a good substance for the neurons to grow on without change to their physiological properties, it would be difficult to distribute the interface to every neuron in a fully developed brain. The interface investigated is a structure on which the neurons adhere as they grow, and is less compatible with integration into an already existing structure.
However, this doesn’t preclude its use in developed brains for cyborg prosthesis and enhancement! The paper pointed out the use of such an interface for brain-damage repair and sensory restoration therapies. Targeted use of such an interface to a small brain region may be much more feasible. Imagine injecting a graphene interface onto a damaged or even epileptic area, and using that interface to direct neural activity. One might even grow brain repair tissue on a graphene structure for coordination of synaptic connections. This could allow clinicians to grow patient-specific brain tissue in a dish with a useful, pre-loaded synaptic structure. (Of course, we’re not sure how we’d know what synaptic connections or structure we might need yet. This is where we venture further into SciFi).
For the near future, implanting this programmed tissue could immediately restore some brain functions (more sensory perceptions and motor skills than personality). The graphene interface might even be programmed to assist synaptic plasticity and repair mechanisms to encourage innervation and long-term recovery. The bumbling Inspector could probably have benefited from some brain repair and cognitive enhancements…
But that’s just a small section of the brain. And it’s mostly cortical surface repair–near the outer edges of the brain.
If we wanted a brain for which every neuron was connected to a graphene interface, for a really complex cyborg, we’d probably have to grow it from scratch.
The programmable nature of an electronic system might mean we could program how that brain developed, and what synaptic connections it kept, through the hijacking of the “what fires together, wires together” rule I mentioned earlier. This graphene interface seems to be equipped to stimulate firing or potentially depress firing, rather than directly stimulate the outgrowth of new neuronal processes for further dendritic and axonal connections. Thus, complementing a binary “fire/depress” control with normal developmental pathways, we might eventually grow and program a brain with total specification (again, total SciFi here) …
But is the brain we’ve grown a biological computer at this point? Or does some element of human autonomy, dignity, and independence still exist? The answer would likely depend on how good we were at programming a developing brain, and what we chose to specify or leave to environmental or genetic influence without direct choice on the clinician’s part.
What happens if someone hacks into this grown and programmed brain? Are they hacking a biological computer or a human being?
Regardless of how far into the realm of science fiction we Go-Go-Gadget, the potentials of graphene for building neuro-interfaces is exciting, and further blurs the line between brain and computer, human and electronic prosthesis. We should use this to its full advantage for brain repair and therapy, but we should also consider how much we wish to exert direct control over how our brains, or new brains we bring into being, work. At what point are we human, cyborg, or biological machine, and should we assign value to such distinctions at all?
- Fabbro, Alessandra, et al. “Graphene-Based Interfaces do not Alter Target Nerve Cells.” ACS nano (2015).