In a loud, crowded restaurant, having the ability to focus on the people and conversation at your own table is critical. Nerve cells in the brain face similar challenges in separating wanted messages from background chatter. A key element in this process appears to be oxytocin, typically known as the “love hormone” for its role in promoting social and parental bonding.
In a study appearing online August 4 in Nature, NYU Langone Medical Center researchers decipher how oxytocin, acting as a neurohormone in the brain, not only reduces background noise, but more importantly, increases the strength of desired signals. These findings may be relevant to autism, which affects one in 88 children in the United States.
“Oxytocin has a remarkable effect on the passage of information through the brain,” says Richard W. Tsien, DPhil, the Druckenmiller Professor of Neuroscience and director of the Neuroscience Institute at NYU Langone Medical Center. “It not only quiets background activity, but also increases the accuracy of stimulated impulse firing. Our experiments show how the activity of brain circuits can be sharpened, and hint at how this re-tuning of brain circuits might go awry in conditions like autism.”
Children and adults with autism-spectrum disorder (ASD) struggle with recognizing the emotions of others and are easily distracted by extraneous features of their environment. Previous studies have shown that children with autism have lower levels of oxytocin, and mutations in the oxytocin receptor gene predispose people to autism. Recent brain recordings from people with ASD show impairments in the transmission of even simple sensory signals.
The current study built upon 30-year old results from researchers in Geneva, who showed that oxytocin acted in the hippocampus, a region of the brain involved in memory and cognition. The hormone stimulated nerve cells – called inhibitory interneurons – to release a chemical called GABA. This substance dampens the activity of the adjoining excitatory nerve cells, known as pyramidal cells.
“From the previous findings, we predicted that oxytocin would dampen brain circuits in all ways, quieting both background noise and wanted signals,” Dr. Tsien explains. “Instead, we found that oxytocin increased the reliability of stimulated impulses – good for brain function, but quite unexpected.”
To resolve this paradox, Dr. Tsien and his Stanford graduate student Scott Owen collaborated with Gord Fishell, PhD, the Julius Raynes Professor of Neuroscience and Physiology at NYU Langone Medical Center, and NYU graduate student Sebnem Tuncdemir. They identified the particular type of inhibitory interneurons responsible for the effects of oxytocin: “fast-spiking” inhibitory interneurons.
The mystery of how oxytocin drives these fast-spiking inhibitory cells to fire, yet also increases signaling to pyramidal neurons, was solved through studies with rodent models. The researchers found that continually activating the fast-spiking inhibitory neurons – good for lowering background noise – also causes their GABA-releasing synapses to fatigue. Accordingly, when a stimulus arrives, the tired synapses release less GABA and excitation of the pyramidal neuron is not dampened as much, so that excitation drives the pyramidal neuron’s firing more reliably.
“The stronger signal and muffled background noise arise from the same fundamental action of oxytocin and give two benefits for the price of one,” Dr. Fishell explains. “It’s too early to say how the lack of oxytocin signaling is involved in the wide diversity of autism-spectrum disorders, and the jury is still out about its possible therapeutic effects. But it is encouraging to find that a naturally occurring neurohormone can enhance brain circuits by dialing up wanted signals while quieting background noise.”
Funding for this work was provided by the Burnett Family Fund, the Mosbacher Fund, the Mathers Foundation, the National Institute of Mental Health (MH071739), the National Institute of Neurological Disorders and Stroke (NS024067), and the Simons Foundation.
About NYU Langone Medical Center:
NYU Langone Medical Center—a world-class, patient-centered, integrated, academic medical center—is one of the nation’s premier destinations for excellence in patient care, biomedical research, and medical education. Located in the heart of Manhattan, NYU Langone is composed of Tisch Hospital, its flagship acute care facility; the Hospital for Joint Diseases, a dedicated inpatient orthopaedic hospital; Hassenfeld Pediatric Center, a comprehensive pediatric hospital supporting a full array of children’s health services; Rusk Rehabilitation, the #1 rehab program in New York since U.S. News & World Report began its hospital rankings in 1989; and a growing ambulatory care network with locations throughout Manhattan, the outer boroughs, and the tri-state area, bringing services directly to where its patients live and work. An integral part of NYU Langone, NYU School of Medicine has trained thousands of physicians and scientists who have helped to shape the course of medical history and enrich the lives of countless people since 1841. NYU Langone's tri-fold mission to serve, teach, and discover is achieved 365 days a year. For more information, go to http://www.NYULMC.org.
Craig Andrews | EurekAlert!
The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
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