Optogenetics researcher develops wireless brain stimulator

June 28, 2011 by Bob Yirka report
Image: Ed Boyden

(Medical Xpress) -- In a major step forward in optogenetics, MIT researcher Christian Wentz has developed a sort of wireless hat that can be used to transmit light to photo sensitized cells in the brain, thus stimulating them to fire when struck by light, or to cease firing, whichever has been programmed for. Previously such optical therapies were done by connecting a light source to a cable or tether to deliver the power for the light sources (lasers or LEDs); now as described in a paper he and his colleagues have published in the Journal of Neural Engineering, a transmitter can be used to create a magnetic field, which in turn is converted to electricity in a tiny hat placed atop a mouse’s head, that is then used to power the implanted light sources.

Over the past several years, the field of optogenetics has arisen, mostly due to the efforts of Ed Boyd, a former physicist and electrical engineer. Optogenetics is where brain (neurons) are coaxed into growing their own photo receptors by inserting the genes of other cells, such as green algae, that naturally respond to light, into the neurons being studied. When light is applied, the newly grown photo receptors open and allow the flow of positively charged ions to interact with the normal firing mechanism of the neurons, which means they can be controlled with an external source, in this case light.

The whole purpose of such research is to find out if such devices might help people who suffer from brain disorders such as epilepsy, which is in essence, a disorder of the brain where neurons begin firing all willy nilly causing an electrical storm of sorts, resulting in convulsions. If certain neurons that exist within the brain that are normally supposed to control such outbursts could be stimulated via light, then the storm could perhaps be headed off before it ever really gets going, thus eliminating the convulsions altogether.

The newly developed hat developed by Wentz, controlled by a computer via USB port, will allow researchers to study the way neurons in the brain work in much more natural situations. Without a tether, subjects (mice) under study should be able to move around the way they normally would in their normal environment, which of course allows the brain to function as it would were it not in a lab; the optimal situation, of course, for studying how the brain works.

This video is not supported by your browser at this time.
Video: TED conference. Ed Boyden shows how, by inserting genes for light-sensitive proteins into brain cells, he can selectively activate or de-activate specific neurons with fiber-optic implants. With this unprecedented level of control, he's managed to cure mice of analogs of PTSD and certain forms of blindness. On the horizon: neural prosthetics.

Explore further: Controlling brain circuits with light

More information: A wirelessly powered and controlled device for optical neural control of freely-behaving animals, Christian T Wentz et al 2011 J. Neural Eng. 8 046021 doi:10.1088/1741-2560/8/4/046021

Optogenetics, the ability to use light to activate and silence specific neuron types within neural networks in vivo and in vitro, is revolutionizing neuroscientists' capacity to understand how defined neural circuit elements contribute to normal and pathological brain functions. Typically, awake behaving experiments are conducted by inserting an optical fiber into the brain, tethered to a remote laser, or by utilizing an implanted light-emitting diode (LED), tethered to a remote power source. A fully wireless system would enable chronic or longitudinal experiments where long duration tethering is impractical, and would also support high-throughput experimentation. However, the high power requirements of light sources (LEDs, lasers), especially in the context of the extended illumination periods often desired in experiments, precludes battery-powered approaches from being widely applicable. We have developed a headborne device weighing 2 g capable of wirelessly receiving power using a resonant RF power link and storing the energy in an adaptive supercapacitor circuit, which can algorithmically control one or more headborne LEDs via a microcontroller. The device can deliver approximately 2 W of power to the LEDs in steady state, and 4.3 W in bursts. We also present an optional radio transceiver module (1 g) which, when added to the base headborne device, enables real-time updating of light delivery protocols; dozens of devices can be controlled simultaneously from one computer. We demonstrate use of the technology to wirelessly drive cortical control of movement in mice. These devices may serve as prototypes for clinical ultra-precise neural prosthetics that use light as the modality of biological control.

Related Stories

Controlling brain circuits with light

May 3, 2011

F1000 Biology Reports, the open-access, peer-reviewed journal from Faculty of 1000, today published a historical account of the beginnings of the optogenetic revolution by Edward Boyden.

Recommended for you

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

No cable spaghetti in the brain

November 24, 2015

Our brain is a mysterious machine. Billions of nerve cells are connected such that they store information as efficiently as books are stored in a well-organized library. To this date, many details remain unclear, for instance ...

Neurons encoding hand shapes identified in human brain

November 23, 2015

Neural prosthetic devices, which include small electrode arrays implanted in the brain, can allow paralyzed patients to control the movement of a robotic limb, whether that limb is attached to the individual or not. In May ...

Wireless sensor enables study of traumatic brain injury

November 23, 2015

A new system that uses a wireless implant has been shown to record for the first time how brain tissue deforms when subjected to the kind of shock that causes blast-induced trauma commonly seen in combat veterans.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.