Our Brain on Drugs: Methylphenidate Edition
For years, ADHD and many other learning disorders have been a question mark due to the fact that the amount of research and scientific revelations have been at a minimum. However, recent studies centering around the brain showing the effects of certain drugs have highlighted the need for further discovery into this novel field.
ADHD or attention deficit hyperactivity disorder is caused by processes in the brain that control management or function. People with this disorder may have trouble memorizing or recalling facts, internalizing anger, problem-solving, and finishing a task thoroughly. These difficulties can prove challenging in school or work environments and even at home.
Recently, scientists at the Okinawa Institute of Science and Technology have taken upon themselves to further study the drug that is used to treat ADHD. They hope that with research into methylphenidate, a stimulant drug, they can develop more accurate treatments that correctly target certain parts of the brain relating to this disorder. They hypothesized that people with the disorder have less dopamine released from neurons when a reward is expected rather than when a reward is given. This means that many feel disconnected from an activity if they don’t expect an immediate positive outcome. Methylphenidate may influence dopamine levels and thereby maintain focus in patients with ADHD. Dr. Furukawa and her colleagues developed a study to see how the medication affects the ventral striatum, a region related to reward system feeling, and where dopamine is released. Using an fMRI, a machine that measures brain activity related to blood flow, scientists scanned brains of those with and without ADHD as they played a video game. There were two Japanese symbols in the game, one that they quickly recognized to be associated with reward and the other not. When individuals with ADHD took the placebo, neuronal activity in the ventral striatum was similar in response to both the reward predicting and non-reward predicting cue. However, when these individuals took the drug, activity in the ventral striatum increased only in response to a reward cue. This way, researchers concluded that once taking the drug, individuals could more easily discriminate between the two cues.
Researchers also studied how the activity of the ventral striatum related to activity in the medial prefrontal cortex, an area that involves decision making. With individuals who took the placebo, neuronal activity in the striatum correlated strongly with activity in the prefrontal cortex at the right moment the reward was delivered. They concluded that the people with ADHD have a medial prefrontal cortex and a ventral striatum that communicate more actively.
Norepinephrine, a neurotransmitter involved in reward-motivated behavior, may be involved and released by multiple neurons in the prefrontal cortex. Scientists reasoned that the drug increased levels of norepinephrine in the prefrontal cortex, which regulates dopamine firing whenever rewards are delivered.
This new insight into the effects of this ADHD medication can help scientists develop better treatments towards ADHD while helping parents of children with the disorder greatly. Delving into this and many such disorders can aid parents and teachers who struggle to cater to the many students and their own learning styles. Hopefully, in the future, more knowledge and discoveries can ease the uncertainty surrounding many such learning disorders.
Citations:
Okinawa Institute of Science and Technology (OIST) Graduate University. "Rich rewards: Scientists reveal ADHD medication's effect on the brain: Researchers scan the brain to uncover how medication for ADHD affects the brain's reward system." ScienceDaily. ScienceDaily, 17 January 2020. <www.sciencedaily.com/releases/2020/01/200117100257.htm>.
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