Methylphenidate (Ritalin) elevates norepinephrine levels in the brains of rats to help focus attention while suppressing nerve signal transmissions in the sensory pathways to make it easier to block out extraneous stimuli, a Philadelphia research team has found.
Their report in the Journal of Neurophysiology helps explain how a stimulant aids people with attention deficit and hyperactivity disorders to improve their focus without increasing their motor activity. Methylphenidate, prescribed under the brand name Ritalin, has been used for more than 20 years, mostly in children, to treat attention deficit hyperactivity disorder (ADHD) and attention deficit disorder (ADD). The drug can also help people who dont suffer either disorder to attend better to a cognitive task.
Despite its wide use, little is known about how the drug, a chemical cousin of amphetamines, produces its therapeutic effects. Researchers want to unlock the mystery of why the drug has the paradoxical effect of decreasing hyperactive behavior and increasing the ability to focus, even though it is a stimulant, said Barry Waterhouse, the studys senior author.
In addition, the researchers found that the higher dose caused the rats to increase motor activity, while the lower dose did not.
Scientists still have much to learn about methylphenidate, which has an impact on neural circuits throughout the entire brain, not just the sensory pathway studied in this paper, Waterhouse noted. The changes that occur in this sensory pathway may affect other areas of the brain and changes in other areas of the brain may affect this pathway. In addition to sensory pathways, other scientists are studying how the drug affects cognitive and emotional areas of brain.
"This experiment adds to our knowledge of what the drug is doing at the cellular level and gives us a springboard to other studies," Waterhouse said. "One question now is, how does the individuals perception of what is an important stimulus factor into the equation?"
Researchers in this area keep in touch and share their results, Waterhouse said. One group, for example, is looking at the drugs effects on dopamine and norepinephrine in the prefrontal cortex, he noted. These results will eventually have to be combined, as changes in one area of the brain are likely to affect other areas.
"Weve been thinking about this for a long time," Waterhouse said of his research. "We hope to have a good idea of the drugs action when we put it all together."
One broad question that intrigues researchers is whether ADHD traces back to the same area of the brain as attention deficit disorder, a similar condition but one in which hyperactivity isnt a symptom.
They also want to know whether Ritalin has any toxic or long-lasting effects, not only for ADHD patients, but also for individuals taking the drug who do not suffer from ADHD or ADD. Methylphenidate use is on the rise among college students who solicit prescriptions from friends or siblings diagnosed with ADHD and use the drug to postpone fatigue and stay alert and focused while studying for exams or completing projects, Waterhouse said.
Christine Guilfoy | EurekAlert!
Speed data for the brain’s navigation system
06.12.2016 | Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE)
Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University
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...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering