A new tool for precise brain mapping. Non-invasive, neuron-specific localized stimulation by near-IR fiber optic beam (red) vs. invasive, non-localized stimulation by blue light (credit: S. Mohanty/UT Arlington) A new tool that could help map and track the interactions between neurons in different areas of the brain is being developed by University of Texas Arlington assistant professor of physics Samarendra Mohanty.
The technology would be useful in the BRAIN (Brain Research Through Advancing Innovative Neurotechnologies) mapping initiative. This new method, which uses a fiber-optic, two-photon, optogenetic stimulator, has been used on human cells in a laboratory, but is also expected to work in vivo. “Scientists have spent a lot of time looking at the physical connections between different regions of the brain. How it works (a) Schematic of conventional two-photon stimulation scanning pattern of targeted cell with laser beam delivered by microscope. A ‘light switch’ in the brain illuminates neural wiring.
Virus-induced optogenetic labeling of neurons; right: closeup of rectangular area (credit: Sheng-Jia Zhang et al. /Science) In a vivid example of how neuroscientists are meticulously tracing the microwiring of the brain, Norwegian researchers have used an optogenetic light switch to see (literally) which neurons communicate with each other in one small section of the brain. The researchers at the Norwegian University of Science and Technology (NTNU)’s Kavli Institute of Systems Neuroscience use a virus that acts as a pathway for delivering “channelrhodopsin-2″ genes to specific “place cells” to create the equivalent of a light switch. Place cells, located in the hippocampus. are dedicated to recognizing specific physical places.
Then the researchers inserted optical fibers in the rat’s brain to transmit light to the place cells. Tiny wireless LED activates neurons to release dopamine. This implantable LED light can activate brain cells to release dopamine and is smaller than the eye of a needle (credit: John A Rogers and Michael R. Bruchas/Washington University) Researchers at Washington University School of Medicine in St.
Louis and the University of Illinois at Urbana-Champaign have developed tiny devices containing light-emitting diodes (LEDs) the size of individual neurons that activate brain cells with light. “This strategy should allow us to identify and map brain circuits involved in complex behaviors related to sleep, depression, addiction, and anxiety,” says co-principal investigator Michael R. “Understanding which populations of neurons are involved in these complex behaviors may allow us to target specific brain cells that malfunction in depression, pain, addiction and other disorders.”
This was the first application of the devices in optogenetics, which uses light to stimulate targeted pathways in the brain. Stimulating neurons in the brain wirelessly. Optogenetic/PET-scan technique for mapping brain activity in moving rats. Immunolabeling of gene expression in the brain following optogenetic stimulation in rats (credit: P. K.
Thanos et al. /JNEUROSCI) A technique that uses light-activated proteins to stimulate particular brain cells and positron emission tomography (PET) scans to trace their effects throughout the entire brain of fully-awake, moving animals has been developed by U.S. Department of Energy’s Brookhaven National Laboratory The method will allow researchers to map exactly which downstream neurological pathways are activated or deactivated by stimulation of targeted brain regions, and how that brain activity correlates with particular behaviors and/or disease conditions. “Because the animals are awake and able to move during stimulation, we can also directly study how their behavior correlates with brain activity,” he said. Optogenetics combined with PET scans The scientists used a modified virus to deliver a light-sensitive protein to particular brain cells in rats.
Controlling Brains With a Flick of a Light Switch. Stopped at a red light on his drive home from work, Karl Deisseroth contemplates one of his patients, a woman with depression so entrenched that she had been unresponsive to drugs and electroshock therapy for years. The red turns to green and Deisseroth accelerates, navigating roads and intersections with one part of his mind while another part considers a very different set of pathways that also can be regulated by a system of lights. In his lab at Stanford University’s Clark Center, Deisseroth is developing a remarkable way to switch brain cells off and on by exposing them to targeted green, yellow, or blue flashes.
With that ability, he is learning how to regulate the flow of information in the brain. Deisseroth’s technique, known broadly as optogenetics, could bring new hope to his most desperate patients. Today, those breakthroughs have been demonstrated in only a small number of test animals. For all its complexity, the brain in some ways is a surprisingly simple device. Optogenetics: technology for modifying your brain and your behavior « Canadian Liberty. Controlling Brains With a Flick of a Light Switch discovermagazine.com | September 25, 2012 “Using the new science of optogenetics, scientists can activate or shut down neural pathways, altering behavior and heralding a true cure for psychiatric disease . …” We’re supposed to believe this technology is going to be used primarily for good (if that was possible).
Is altering or damaging the brain going to “cure” psychiatric conditions? I don’t believe it. “…In his lab at Stanford University’s Clark Center, Deisseroth is developing a remarkable way to switch brain cells off and on by exposing them to targeted green, yellow, or blue flashes….“… When sunlight hits the opsin, it instantly sends an electric signal through the microbe’s cell membrane, telling the tiny critter which way to turn in relation to the sun. Optogenetics: Controlling the Brain with Light [Extended Version] Despite the enormous efforts of clinicians and researchers, our limited insight into psychiatric disease (the worldwide-leading cause of years of life lost to death or disability) hinders the search for cures and contributes to stigmatization.
Clearly, we need new answers in psychiatry. But as philosopher of science Karl Popper might have said, before we can find the answers, we need the power to ask new questions. In other words, we need new technology. Developing appropriate techniques is difficult, however, because the mammalian brain is beyond compare in its complexity. It is an intricate system in which tens of billions of intertwined neurons—with multitudinous distinct characteristics and wiring patterns—compute with precisely timed, millisecond-scale electrical signals, as well as with a rich diversity of biochemical messengers.
Optogenetics is the combination of genetics and optics to control well-defined events within specific cells of living tissue. Related links: Retinitis pigmentosa - National Library of Medicine - PubMed Health. In Optogenetics, Buttons for Neural Switchboards. Optogenetics illuminates pathways of motivation through brain. Whether you are an apple tree or an antelope, survival depends on using your energy efficiently. In a difficult or dangerous situation, the key question is whether exerting effort -- sending out roots in search of nutrients in a drought or running at top speed from a predator -- will be worth the energy.
In a paper published online Nov. 18 in Nature, Karl Deisseroth, MD, PhD, a professor of bioengineering and of psychiatry and behavioral sciences at Stanford University, and postdoctoral scholar Melissa Warden, PhD, describe how they have isolated the neurons that carry these split-second decisions to act from the higher brain to the brain stem. In doing so, they have provided insight into the causes of severe brain disorders such as depression. In organisms as complex as humans, the neural mechanisms that help answer the question, "Is it worth my effort? " can fail, leading to debilitating mental illnesses. Light coercion The secret is as old as green algae. Working backward Larger puzzles.