Ritalin — a popular medication prescribed to treat attention deficit disorder — may not only help in enhancing a person’s ability to focus and concentrate. New animal research suggests it may also help enhance the speed of learning.
In the new animal study, researchers show that Ritalin boosts both focus and speed of learning by increasing the activity of the neurotransmitter dopamine deep inside the brain.
Neurotransmitters are the chemical messengers neurons use to communicate with each other. They release the molecule, which then docks onto receptors of other neurons. The research demonstrated that one type of dopamine receptor aids the ability to focus, and another type improves the learning itself.
The scientists also established that Ritalin produces these effects by enhancing brain plasticity — strengthening communication between neurons where they meet at the synapse. Research in this field has accelerated as scientists have recognized that our brains can continue to form new connections — or remain plastic, that is, flexible — throughout life.
“Since we now know that Ritalin improves behavior through two specific types of neurotransmitter receptors, the finding could help in the development of better targeted drugs, with fewer side effects, to increase focus and learning,” said Antonello Bonci, MD, principal investigator at the Ernest Gallo Clinic and Research Center and professor of neurology at University of California – San Francisco.
Bonci and his colleagues showed that Ritalin’s therapeutic action takes place in a brain region called the amygdala, an almond-shaped cluster of neurons known to be critical for learning and emotional memory.
“Although Ritalin is so frequently prescribed, it induces many brain changes, making it difficult to identify which of those changes improve learning,” noted lead author of the new research, Kay Tye, PhD.
“By identifying the brain mechanisms underlying Ritalin’s behavioral enhancements, we can better understand the action of Ritalin as well as the properties governing brain plasticity.”
The research assessed the ability of rats to learn that they could get a sugar water reward when they received a signal — a flash of light and a sound. The scientists compared the behavior of animals receiving Ritalin with those that did not receive it, and found those receiving Ritalin learned much better.
However, they also found that if they blocked the dopamine D1 receptors with drugs, Ritalin was unable to enhance learning. And if they blocked D2 receptors, Ritalin failed to improve focus. The experiments established the distinct role of each of the dopamine receptors in enabling Ritalin to enhance cognitive performance.
In addition, animals that performed better after Ritalin treatment showed enhanced synaptic plasticity in the amygdala. Enhanced plasticity is essentially increased efficiency of neural transmission. The researchers confirmed this by measuring electrical activity in neurons in the amygdala after Ritalin treatment.
The research confirmed that learning and focus were enhanced when Ritalin was administered to animals in doses comparable to those used therapeutically in children.
The study was published online in Nature Neuroscience on Sunday, March 7.
Source: University of California – San Francisco