Producing accurate and stable, long-term readings of neuronal activity using a brain–machine interface (BMI) is now possible thanks to work by Naotaka Fujii and his colleagues at the RIKEN Brain Science Institute, Wako1. Their results could help researchers to develop durable and versatile neural prostheses for rehabilitation patients.
BMIs read neural activity associated with planning and executing movements and decode it into commands that are relayed to an external device such as a computer cursor or robotic arm. This normally involves recording simultaneously from multiple, single neurons, so the recordings are unstable and the decoding model needs re-calibration on a daily basis.
Fujii and colleagues used an alternative technique called electrocorticography, in which an array of electrodes is used to record the population activity of cortical neurons.
Electrocorticography is often used to evaluate epileptic patients before neurosurgery but is not normally used for longer than two weeks. It was thought to provide a low fidelity signal for BMIs, because the electrodes record neural activity from the cortical surface, rather than within the cortex.
To overcome this, the researchers designed an electrode array for long-term recording, and developed a novel decoding algorithm that samples neural activity from multiple brain regions.
After implanting the electrodes into the brains of monkeys, so that they spanned multiple brain regions, Fujii and colleagues trained the animals to spontaneously reach out and grasp food presented to them. The monkeys wore custom-made jackets fitted with reflective markers at the shoulders, elbows and wrists. The researchers then recorded the monkeys’ arm movements using a motion capture system, and correlated them with the neuronal activity recorded by the electrodes.
By decoding the signals, they could predict the trajectory and orientation of the monkeys’ arms in three dimensions. The accuracy of the decoding was comparable to that of existing BMIs which record activity from single cells. Furthermore, the recordings were highly stable, and could be decoded for several months without recalibration.
The new recording technique should prove to be useful for researchers investigating movement control and higher cognitive functions. It could also lead to versatile devices that can be implanted for long periods of time, to aid patients with brain damage, spinal cord injury, and neurodegenerative conditions such as amyotrophic lateral sclerosis, notes Fujii.
“Our electrode array is still not ready for long-term use in patients, because of the risk of infection,” says Fujii, “but we are now developing a fully implantable wireless device to prevent this.”
The corresponding author for this highlight is based at the Laboratory for Adaptive Intelligence, RIKEN Brain Science Institute
1. Chao, Z.C., Nagasaka, Y. & Fujii, N. Long-term asynchronous decoding of arm motion using electrocorticographic signals in monkeys. Frontiers in Neuroengineering 3, 3–13 (2010)
gro-pr | Research asia research news
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences