The work, described this week in the journal Nature Neuroscience, has implications for the future study of smell and of complex perception systems that do not lend themselves to easy study with traditional methods.
"It makes intuitive sense to use odors to study smell," says Venkatesh N. Murthy, professor of molecular and cellular biology at Harvard. "However, odors are so chemically complex that it is extremely difficult to isolate the neural circuits underlying smell that way."
Murthy and his colleagues at Harvard and Cold Spring Harbor Laboratory used light instead, applying the infant field of optogenetics to the question of how cells in the brain differentiate between odors.
Optogenetic techniques integrate light-reactive proteins into systems that usually sense inputs other than light. Murthy and his colleagues integrated these proteins, called channelrhodopsins, into the olfactory systems of mice, creating animals in which smell pathways were activated not by odors, but rather by light.
"In order to tease apart how the brain perceives differences in odors, it seemed most reasonable to look at the patterns of activation in the brain," Murthy says. "But it is hard to trace these patterns using olfactory stimuli, since odors are very diverse and often quite subtle. So we asked: What if we make the nose act like a retina?"
With the optogenetically engineered animal, the scientists were able to characterize the patterns of activation in the olfactory bulb, the brain region that receives information directly from the nose. Because light input can easily be controlled, they were able to design a series of experiments stimulating specific sensory neurons in the nose and looking at the patterns of activation downstream in the olfactory bulb.
"The first question was how the processing is organized, and how similar inputs are processed by adjacent cells in the brain," Murthy says.
But it turns out that the spatial organization of olfactory information in the brain does not fully explain our ability to sense odors. The temporal organization of olfactory information sheds additional light on how we perceive odors. In addition to characterizing the spatial organization of the olfactory bulb, the new study shows how the timing of the "sniff" plays a large part in how odors are perceived.
The paper has implications not only for future study of the olfactory system, but more generally for teasing out the underlying neural circuits of other systems.
Murthy's co-authors on the Nature Neuroscience paper are Ashesh K. Dhawale of Cold Spring Harbor Laboratory and the National Centre for Biological Sciences in Bangalore, India, Akari Hagiwara of Harvard, Upinder S. Bhalla of the National Centre for Biological Sciences, and Dinu F. Albeanu of Cold Spring Harbor Laboratory. Their work was sponsored by Harvard and Cold Spring Harbor Laboratory.
Steve Bradt | EurekAlert!
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine