Wireless mice, batteries not included (optrodes and electrodes in one wireless contraption)

A neuron is expressing the light-gated cation channel channelrhodopsin-2 (small green shapes), and is being illuminated by a focused beam of blue light (coming from the top). The opsins have opened, depolarizing or electrically activating the cell. The pulse of electricity spreads throughout the inside of the cell (white highlights), triggering the release of neurotransmitters to downstream cells. Credit: Ed Boyden and Massachusetts Institute of Technology McGovern Institute. Courtesy: National Science Foundation

Optogenetics is the new (and very popular) kid on the block of neurotechniques arsenal. Before optogenetics, in order to manipulate how the neurons behave in a particular brain region, one had to do so electrically or chemically by inserting into that region an electrode or a tube, respectively. The trouble with that is that you never know exactly which neurons you are manipulating, given that any brain regions has many kinds of cells that project to many other regions and they are not nicely arranged in clumps but interspersed in a messy mesh. But with optogenetics, you can select exactly which neurons you want to manipulate. You take a mouse and you genetically engineer it to express in your favorite neurons a particular protein that is sensitive to a certain light wavelength (like a rhodopsin). Then, you shine the light in the mouse’s brain, turning on and off the neurons of your interest. The technique, besides having tremendous success in fundamental research, also shows promise for neuroprosthetics for some diseases, like Parkinson’s.

Despite rapid improvements of the technique due to increasing demand form the neuroscience community, it is still difficult to record from the freely-moving animal, mainly because the animal is attached to the fiber optic that delivers the light pulses. There have been some wireless attempts (some successful), but because the resultant contraption was too big and heavy for the animal, they have reduced options as compared to the wired devices. Gagnon-Turcotte et al. (2015) describe here a way to build a wireless headtsage that can deliver light pulses AND record the electrophysiological activity of the neurons. And, equally important, is cheap and can be build with off-the-shelf components.

Reference: Gagnon-Turcotte, G., Kisomi, A. A., Ameli, R., Camaro, C.-O. D., LeChasseur, Y., Néron, J.-L., , Bareil, P. B., Fortier, P., Bories, C., de Koninck, Y., & Gosselin, B. (9 September 2015). A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability. Sensors, 15(9): 22776-22797; doi:10.3390/s150922776. Article + FREE PDF

By Neuronicus, 22 September 2015

Update (27 September 2015). The author Gabriel Gagnon-Turcotte wins the Mitacs 2015 prize for exceptional innovation for the development of a wireless system to study the brain