A new American study has found that Ritalin boosts learning by increasing brain plasticity.
Scientists conducted the research on rats to demonstrate, for the first time, that Ritalin boosts the ability to focus on tasks and enhances the speed of learning by increasing the activity of the neurotransmitter dopamine inside the brain.
The study, appearing online in Nature Neuroscience, also showed that one type of dopamine receptor aids the ability to focus, and another type improves the learning itself.
Antonello Bonci, co-senior author of the paper and professor of neurology at UCSF, said: "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."
Bonci is also the principal investigator at the Ernest Gallo Clinic and Research Center, which is affiliated with the UCSF Department of Neurology.
Bonci and his team 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.
Patricia Janak, co-senior author on the paper, said: "We found that a dopamine receptor, known as the D2 receptor, controls the ability to stay focused on a task - the well-known benefit of Ritalin.
"But we also discovered that another dopamine receptor, D1, underlies learning efficiency."
Janak is a principal investigator at the Gallo Center and a UCSF associate professor of neurology. Lead author of the paper is Kay M. Tye, PhD, a postdoctoral scientist at the Gallo Center when the research was carried out.
The research analysed 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 behaviour of animals receiving Ritalin with those that did not receive it, and found those receiving Ritalin learned much better.
But they also discovered 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.
Moreover, 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 improved when Ritalin was administered to animals in doses comparable to those used therapeutically in children.
Kay Tye said: "Although Ritalin is so frequently prescribed, it induces many brain changes, making it difficult to identify which of those changes improve learning."
"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."