Logo: University of Southern California

USC Engineers Use Nanotechnology to Mimic Brain Synapse

Devices might be used in brain prostheses – or even combined into massive network of synthetic neurons to create a synthetic brain
Robert Bradford
April 27, 2011 —

Alice Parker, seated, with Chih-Chieh Hsu, center, and Jonathan Joshi
Researchers at the USC Viterbi School of Engineering have made a significant step in the use of nanotechnologies to mimic brain functions. They have built a carbon nanotube circuit whose behavior in tests reproduces the function of a neuron input, the synapse, a key building block of the brain.

The team, which was led by professors Alice Parker and Chongwu Zhou in the Ming Hsieh Department of Electrical Engineering, used an interdisciplinary approach combining circuit design with nanotechnology to address the complex problem of capturing brain function.

In a paper published in the Proceedings of the Life Science Systems and Applications Workshop in April 2011, the USC engineers detailed how they were able to use carbon nanotubes to create a synapse. Carbon nanotubes are molecular carbon structures with walls one carbon atom thick. They are extremely tiny, with a diameter a million times smaller than a pencil point. These nanotubes can be used in electronic circuits, acting as metallic conductors or semiconductors.

“This is a necessary first step in the process,” said Parker, who began the complex project of looking at the possibility of developing a synthetic brain in 2006. “We wanted to answer the question: Can you build a circuit that would act like a neuron? The next step is even more complex. How can we build structures out of these circuits that mimic the neuron, and eventually the function of the brain, which has 100 billion neurons and 10,000 synapses per neuron?”

Chongwu Zhou
Parker emphasized that the fabricated synapse is simplified, the actual development of a synthetic brain is decades away, and she said the next hurdle for the research centers on reproducing brain plasticity in the circuits. The human brain continually produces new neurons and adapts throughout life, and creating this process through analog circuits will be a monumental task, according to Parker.

She believes the ongoing research of understanding the process of human intelligence could have long-term implications for everything from developing nanotechnology prosthetics that would heal traumatic brain injuries to developing intelligent, safe cars that would protect drivers in bold new ways.

Microscopic view showing the nanotube wafers used fabricate the synapse mimic devices

For Jonathan Joshi, a USC Viterbi Ph.D. student who is a co-author of the paper, the interdisciplinary approach to the problem was key to the initial progress. Joshi said that working with Zhou and his group of nanotechnology researchers provided the ideal dynamic of circuit technology and nanotechnology.

“The interdisciplinary approach is the only approach that will lead to a solution. We need more than one type of engineer working on this solution,” said Joshi. “We should constantly be in search of new technologies to solve this problem.”

Other USC  researchers on the team included Jialu Zhang, Chuan Wang, Chih-­‐Chieh Hsu, and Udhay Ravishankar. The research is supported by the National Science Foundation and the Women in Science and Engineering program at USC, part of  the BioRC Biomimetic Real-Time Cortex Project.

Download a poster of the research here.

Download a copy of a paper on the research here.

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