The researchers, at Washington University School of Medicine in St. Louis and the University of Illinois at Urbana-Champaign, developed tiny devices, containing light emitting diodes (LEDs) the size of individual neurons. The devices activate brain cells with light. The scientists report their findings April 12 in the journal Science.
John A. Rogers, PhD and Michael R. Bruchas, PhD
This implantable LED light can activate brain cells to release dopamine and is smaller than the eye of a needle.
“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. Bruchas, PhD, assistant professor of anesthesiology at Washington University. “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.”
For the study, Washington University neuroscientists teamed with engineers at the University of Illinois to design microscale (LED) devices thinner than a human hair. This was the first application of the devices in optogenetics, an area of neuroscience that uses light to stimulate targeted pathways in the brain. The scientists implanted them into the brains of mice that had been genetically engineered so that some of their brain cells could be activated and controlled with light.
Although a number of important pathways in the brain can be studied with optogenetics, many neuroscientists have struggled with the engineering challenge of delivering light to precise locations deep in the brain. Most methods have tethered animals to lasers with fiber optic cables, limiting their movement and altering natural behaviors.
But with the new devices, the mice freely moved about and were able to explore a maze or scamper on a wheel. The electronic LEDs are housed in a tiny fiber implanted deep in the brain. That’s important to the device’s ability to activate the proper neurons, according to John A. Rogers, PhD, professor of materials science and engineering at the University of Illinois.
“You want to be able to deliver the light down into the depth of the brain,” Rogers says. “We think we’ve come up with some powerful strategies that involve ultra-miniaturized devices that can deliver light signals deep into the brain and into other organs in the future.”
Using light from the cellular-scale LEDs to stimulate dopamine-producing cells in the brain, the investigators taught the mice to poke their noses through a specific hole in a maze. Each time a mouse would poke its nose through the hole, that would trigger the system to wirelessly activate the LEDs in the implanted device, which then would emit light, causing neurons to release dopamine, a chemical related to the brain’s natural reward system.
“We used the LED devices to activate networks of brain cells that are influenced by the things you would find rewarding in life, like sex or chocolate,” says co-first author Jordan G. McCall, a neuroscience graduate student in Washington University’s Division of Biology and Biomedical Sciences. “When the brain cells were activated to release dopamine, the mice quickly learned to poke their noses through the hole even though they didn’t receive any food as a reward. They also developed an associated preference for the area near the hole, and they tended to hang around that part of the maze.”
The researchers believe the LED implants may be useful in other types of neuroscience studies or may even be applied to different organs. Related devices already are being used to stimulate peripheral nerves for pain management. Other devices with LEDs of multiple colors may be able to activate and control several neural circuits at once. In addition to the tiny LEDs, the devices also carry miniaturized sensors for detecting temperature and electrical activity within the brain.
Bruchas and his colleagues already have begun other studies of mice, using the LED devices to manipulate neural circuits that are involved in social behaviors. This could help scientists better understand what goes on in the brain in disorders such as depression and anxiety.
“We believe these devices will allow us to study complex stress and social interaction behaviors,” Bruchas explains. “This technology enables us to map neural circuits with respect to things like stress and pain much more effectively.”
The wireless, microLED implant devices represent the combined efforts of Bruchas and Rogers. Last year, along with Robert W. Gereau IV, PhD, professor of anesthesiology, they were awarded an NIH Director’s Transformative Research Project award to develop and conduct studies using novel device development and optogenetics, which involves activating or inhibiting brain cells with light.Funding for this research comes from the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute on Drug Abuse (NIDA) and the NIH Common Fund of the National Institutes of Health (NIH). Other funding comes from the McDonnell Center for Systems Neuroscience, a National Security Science and Engineering Faculty Fellowship of Energy, a US Department of Energy Division of Material Sciences Award, and the Materials Research Laboratory and Center for Microanalysis of Materials.
Washington University School of Medicine’s 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked sixth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.
Jim Dryden | Newswise
Penn first in world to treat patient with new radiation technology
22.09.2017 | University of Pennsylvania School of Medicine
Skin patch dissolves 'love handles' in mice
18.09.2017 | Columbia University Medical Center
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy