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Articles scientifiques sur les nouvelles utlisation de l'optogénétique

Noninvasive brain control. Optogenetics, a technology that allows scientists to control brain activity by shining light on neurons, relies on light-sensitive proteins that can suppress or stimulate electrical signals within cells. This technique requires a light source to be implanted in the brain, where it can reach the cells to be controlled. MIT engineers have now developed the first light-sensitive molecule that enables neurons to be silenced noninvasively, using a light source outside the skull. This makes it possible to do long-term studies without an implanted light source. The protein, known as Jaws, also allows a larger volume of tissue to be influenced at once.

This noninvasive approach could pave the way to using optogenetics in human patients to treat epilepsy and other neurological disorders, the researchers say, although much more testing and development is needed. Mining nature’s diversity To find a better alternative, Boyden, graduate student Amy Chuong, and colleagues turned to the natural world. Virally mediated optogenetic excitation and inhibition of pain in freely moving nontransgenic mice : Nature Biotechnology. Primary authors These authors contributed equally to this work.Shrivats Mohan Iyer & Kate L Montgomery Affiliations Department of Bioengineering, Stanford University, Stanford, California, USA.

Shrivats Mohan Iyer, Kate L Montgomery, Chris Towne, Soo Yeun Lee, Charu Ramakrishnan, Karl Deisseroth & Scott L Delp Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California, USA. Howard Hughes Medical Institute, Stanford University, Stanford, California, USA. Contributions S.M.I., K.L.M., C.T. and S.L.D. designed the experiments. Competing financial interests C.T., K.D., and S.L.D. have a financial interest in Circuit Therapeutics, Inc., which, however, did not support this work.

Author details Shrivats Mohan IyerKate L MontgomeryChris TowneSoo Yeun LeeCharu RamakrishnanKarl DeisserothScott L DelpContact Scott L Delp. Prevalence of chronic pain with neuropathic characteristics in the general population. Qui souffre de douleur ? Molecule Lets Scientists Control Sensory Neurons with Light. A drug-like molecule has been found to let researchers control movements in mice and fish with flashes of light. Unlike similar experiments using a light-based technique known as optogenetics, the new method doesn’t require researchers to genetically engineer animals in order to achieve the neural control. A study published online in today’s Nature Chemical Biology describes a novel approach for controlling neurons and behaviors with light.

Such techniques are powerful research tools for understanding the brain, and may one day be used therapeutically. Today’s report describes a method for using light to control neuronal activity in unmodified animals. Fish given a small molecule called “optovin” will move around very quickly in response to a flash of light, report Massachusetts General Hospital’s David Kokel and colleagues. The team determined that optovin docks onto a specific kind of protein channel that sits in the membrane of nerve cells that are the first to respond to pain.

Optogenetics Makes Mice Resistant to Pain. Some of the mice squeaked in pain when researchers aimed a blue light at their paws. Other mice felt nothing at all when zapped with heat. In the latest demonstration of optogenetics, a versatile but complex technology for controlling nerve cells, a research team at Stanford University has sketched out how patients afflicted by chronic pain might one day find relief: simply by pressing a bright flashlight to their skin. “Patients could be given their own ability to create a pain block on demand,” says Michael Kaplitt, a neurosurgeon and chief scientific officer of Circuit Therapeutics, a three-year-old Palo Alto, California, biotechnology startup now working on a pain treatment along with some of the Stanford scientists. Optogenetics is a breakthrough technology that is giving scientists precise control over what animals feel, how they behave, and even what they think.

But controlling nerves outside the brain could prove easier. Optogenetics Can Calm Seizures in Rats, a Study in Nature Neuroscience Shows. Strobe lights can trigger epileptic seizures. Now imagine a light that stops a seizure a split second after it starts. By applying pulses of light to genetically altered nerve cells deep in rat brains, researchers at Stanford and Pierre and Marie Curie University in France have done just that.

Their results, which showed for the first time how a part of the brain called the thalamus is involved with epileptic seizures, were published today in Nature Neuroscience. The study could point toward new targets for epilepsy treatment, says Ed Boyden, associate professor and leader of the Synthetic Biology Group at MIT. Boyden was not involved in the work. The latest research looked at a kind of seizure that sometimes follows damage to the cerebral cortex, the outer part of the brain, from strokes or head injuries. In the current study, experiments with rats confirmed that the thalamus propagates seizure activity originating in the cortex. False Memories in Mice. Scientists have created a false memory in mice by manipulating neurons that bear the memory of a place.

The work further demonstrates just how unreliable memory can be. It also lays new ground for understanding the cell behavior and circuitry that controls memory, and could one day help researchers discover new ways to treat mental illnesses influenced by memory. In the study, published in Science on Thursday, the MIT scientists show that they can modify a memory and have a mouse believe it experienced something it didn’t. Susumu Tonegawa, a neuroscientist at MIT, and members of his lab used mice that were genetically modified to allow for certain neurons to be activated with a flash of light; the technique enabled the researchers to activate a memory that caused a mouse to believe it had experienced electrical shocks in a particular box, even though no such thing had happened there.

“The process of memory is nothing like a tape recording,” says study co-first author Steve Ramirez. Optogenetics. Stopping heart attacks with light: Optogenetics researchers see opsins as a way to move beyond defibrillators and pacemakers. Graphic courtesy of Patrick M. Boyle Electricity is as blunt a tool as we have in our medical arsenal. Whether it’s an implanted pacemaker or defibrillator paddles on the chest—CLEAR! —using electricity to kick-start a heart feels like getting kicked by a Clydesdale. We use it because it works, but we can’t stop all those volts from ripping through surrounding flesh and bone. Literally. “Wouldn’t it be amazing to shine a light on somebody who’s having a heart attack and you’re able to restore their life?”

It sounds fantastical—more like something out of Men in Black than modern medicine—but the study of optogenetics has already made great strides in neuroscience. Here’s how it works. Treating the heart with this method would also allow medical professionals to target specific areas in need of a low-energy jolt, instead of bathing the whole body in electrical bedlam.