How Ritalin Sharpens Attention – Neuroscience News

Summary: A study sheds new light on the neurobiological mechanisms that occur allowing the ADHD drug Ritalin to improve attention and reports that the drug may have benefits for a range of cognitive changes associated with aging.

Source: University of Pittsburgh

Even half a century after a drug hits the market, scientists can still learn new things about how it works. New research from neuroscientists at the University of Pittsburgh offers rare insight into how Ritalin affects activity in animal brains, providing a deeper understanding of how groups of brain cells regulate brain function. attention and indicating possible new uses for the stimulant.

About 1 in 11 children in the United States are prescribed stimulants like methylphenidate (also known by its brand name Ritalin) to improve attention and concentration in people with attention-deficit/hyperactivity disorder, or ADHD.

Many more adults, about 1 in 5 according to surveys, also use off-label drugs. And while the safety and effectiveness of these drugs are well understood, there is still much to learn about how they work.

“We really know very little about the effect of these drugs on the activity of groups of neurons,” said the study’s lead author, Marlene Cohen, professor of neuroscience at the Kenneth P. Dietrich School of Medicine. Arts and Sciences.

“But basic scientists like us have studied what groups of neurons can tell us about behavior and cognition, and so understanding what these drugs are doing to groups of neurons can perhaps give us clues about other things for which they would be useful.”

Previous work led by Pitt postdoctoral researcher Amy Ni has shown a link between animals’ performance on a visual task and a particular measure of neurons in the visual cortex, specifically the likelihood that they fire independently of each other. others, as opposed to being synchronized.

In the current work, they found that animals that took methylphenidate performed better on a visual attention task, and that the improvement occurred exactly when that same neural activity metric shifted.

The team, led by Ni, published their research in the journal Proceedings of the National Academy of Sciences April 25.

Some of the study results were expected from what is already known about the drug. The three animals took methylphenidate or a placebo alternately for two weeks of testing. On the days they took the drug, they spent more time on the task and were more successful at it, but only when the required task happened in a place they were already paying attention to.

In most neuroscience experiments, researchers target very small groups of neurons with electricity or light. “We definitely didn’t do that — we took those drugs, mixed them in fruit juice, and gave them to the animals,” Cohen said. “It surprised me that a very general manipulation had a very specific behavioral effect.”

In addition to learning more about how the drug works, such experiments allow researchers to better understand how the firing patterns of neurons translate into behaviors such as paying attention to what we see.

By comparing how neurons act when the brain is in different states, such as when a subject has taken or has not taken a drug, researchers can create more complete and useful models of how brain cells and behavior are linked.

It’s an approach that hasn’t received much attention, Cohen said, in part because of a lack of funds to fund research into how drugs alter the activity of neurons. This makes it difficult to find “crossovers”, ie new uses for drugs that are already on the market.

In light of the current study, previous work in the lab suggests some of these potential crosses. Ni’s research has found similarities between neural patterns related to attention and certain types of learning, suggesting that treatments for disorders involving one could be effective for the other.

“These stimulants could actually be useful for treating a lot of things, ranging from cognitive changes associated with normal aging, to Alzheimer’s disease and others,” Cohen said. Although this is currently only a well-informed hunch, it is one of the lab’s projects to pursue in future studies.

For now, this study remains an important first step in a line of research that Cohen hopes to see much more of: connecting the dots between the neural underpinnings of our behavior and how drugs affect it.

“It’s a test, and I think there’s still a lot to do,” she said. “I hope people will see that these approaches are important.”

About this psychopharmacology and attention research news

Author: Press office
Source: University of Pittsburgh
Contact: Press Office – University of Pittsburgh
Picture: Image is in public domain

Original research: Access closed.
“Methylphenidate as a Causal Test of Translational and Basic Neural Coding Hypotheses” by Amy M. Ni et al. PNAS

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Abstract

Methylphenidate as a causal test of translational and basic neural coding hypotheses

Most studies in systems neuroscience fall into one of two categories: basic scientific work aimed at understanding the relationship between neurons and behavior, or translational work aimed at developing treatments for neuropsychiatric disorders.

Here, we use both of these approaches to inform and improve each other.

Our study both tests hypotheses about basic science neural coding principles and elucidates the neural mechanisms underlying the clinically relevant behavioral effects of systemically administered methylphenidate (Ritalin).

We found that orally administered methylphenidate, used clinically to treat attention deficit hyperactivity disorder (ADHD) and generally to improve cognition, increases selective visual attention in space, improving performance visual only at the place frequented.

Moreover, we found that this causal manipulation improves vision in rhesus macaques specifically when it decreases the average correlated variability of neurons in the V4 visual area. Our results demonstrate that the visual system is a platform for understanding the neural underpinnings of complex cognitive processes (basic science) and neuropsychiatric disorders (translation).

Addressing basic scientific assumptions, our results are consistent with a scenario in which methylphenidate has specific cognitive effects by acting through naturally selective cognitive mechanisms.

Clinically, our results suggest that the often incredibly specific symptoms of neuropsychiatric disorders can be caused and treated by exploiting general mechanisms.