Synthetic Brain

Researchers from the University of Southern California have shown that carbon nanotubes may be used to model the functioning of brain cells (neurons). These researchers are designing a carbon nanotube circuit to model the properties of a real brain cell. So far the scientists have only tested computer simulations to see whether it is theoretically possible and have not actually synthesized a carbon nanotube circuit yet. So this may lead to the creation of better artificial neurons and potentially enable the construction of a synthetic electronic brain. I've mentioned in the recent past about using carbon nanotubes to create brain computer interfaces. In that post, I talked about how carbon nanotubes were able to make a working connection between different neurons. Carbon nanotubes are molecular tube shape structures composed of honeycomb patterns of chemically bonded carbon atoms. They conduct electricity and have already found use in a variety of novel technologies. This ability to conduct electricity allows the carbon nanotubes to serve as a communication junction between two neurons. This new research shows they may have even more versatility and usefulness for brain emulation advancement.

The researchers have shown that portions of a neuron can be modeled electronically using carbon nanotube circuit models and have performed detailed simulations of the circuit models. A single archetypical neuron, including excitatory and inhibitory synapses, has been modeled electronically and simulated. Parker and her co-researcher Chongwu Zhou are in the process of combining these circuit models of neurons to create a functional carbon nanotube circuit model of a small network of neurons. This small network of interconnected neurons will be simulated using the carbon nanotube models. This network demonstrates an interesting neural circuit that detects moving edges in a selected direction.
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The actual creation of entire synthetic brains may be quite a ways away, if at all. It may be fairly difficult to actually pull off this type of brain emulation. However, this preliminary research is a step in that direction.

Synthetic brains are a long way from reality, but researchers at the University of Southern California, funded by the National Science Foundation, are taking the first steps to build neurons from carbon nanotubes that emulate human brain function "At this point we still don't know if building a synthetic brain is feasible," said Alice Parker, professor of electrical engineering. "It may take decades to realize anything close to the human brain but emulating pieces of the brain, such as a synthetic vision system or synthetic cochlea that interface successfully with a real brain may be available quite soon, and synthetic parts of the brain's cortex within decades."

Artificial neurons constructed from carbon nanotubes could one day be implanted directly within a person's brain. This could be used to replace missing brain tissue. More sophisticated brain implants may be constructed with this material that would have improved functioning.

Parker believes carbon nanotubes are an ideal material to emulate brain function because their three-dimensional structure allows connectivity in all directions on all planes and because a carbon-based prosthesis is less likely to be rejected by the human body than one made from inorganic materials. But their invasive nature could result in them invading surrounding tissue and prompting lesions and cancers.

Obviously this recent research is similar to the project to construct a neuromorphic chip that the government is undertaking. Neuromorphic engineering seeks to mimic brain functioning on a silicon chip. Carbon nanotube artificial neurons could potentially be used in this manner to create artificially intelligent brains. A neuromorphic chip constructed from carbon nanotubes could be smaller and more efficient than other types of existing electronics. As to whether these artificial neurons could actually replicate the exact functioning of actual neurons is debatable. It will still be a while before we know for sure.

Here is a fairly recent article that discusses more about carbon nanotubes being used as neuron interfaces. This ability to make connections with real neurons could be utilized to seamlessly integrate the artificial neurons into existing brain matter.

The research shows that carbon nanotubes, which, like neurons, are highly electrically conductive, form extremely tight contacts with neuronal cell membranes. Unlike the metal electrodes that are currently used in research and clinical applications, the nanotubes can create shortcuts between the distal and proximal compartments of the neuron, resulting in enhanced neuronal excitability.

It should definitely be interesting to see what happens as the development of this technology matures.