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ADHD drug Ritalin has no effect on primate prefrontal cortex

Researchers observe no difference in neuronal activity after administration of the drug, even at doses that improve monkeys' attention

Society for Neuroscience

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IMAGE: Figure 2a. Location of chronically implanted multielectrode Utah array within the left caudal lateral prefrontal cortex. The shaded pink area roughly represents area 8A in the macaque brain. The blue... view more 

Credit: Tremblay et al., eNeuro (2019)

In contrast to studies of mice and rats, new research published in eNeuro investigating the effect of methylphenidate (Ritalin) on neuronal activity in monkeys has found no effect of the drug on the prefrontal cortex. The study leaves open the question of how and why Ritalin improves attention in humans.

Julio Martinez-Trujillo and colleagues refute their hypothesis the caudal prefrontal cortex-- a brain region critical for attention -- is Ritalin's main site of action in the brain. To arrive at this conclusion, the researchers recorded large populations of neurons in this brain region as two male macaque monkeys performed a demanding visual attention task. The team did not observe any differences in neuronal activity after administration of the drug compared to a placebo, even at doses that improved the monkeys' performance on the task.

These negative results do not rule out other regions of the prefrontal cortex as possible sources of Ritalin's action in the brain. In addition, they highlight the difficulty of translating preclinical research from rodents to nonhuman primates and call for improved collaboration between scientists investigating common questions using different animal models.

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Article: The effects of methylphenidate (Ritalin) on the neurophysiology of the monkey caudal prefrontal cortex
DOI: https://www.eneuro.org/lookup/doi/10.1523/ENEURO.0371-18.2018
Corresponding author: Julio Martinez-Trujillo (Robarts Research Institute, London, Canada), julio.martinez@robarts.ca

About eNeuro

eNeuro, the Society for Neuroscience's open-access journal launched in 2014, publishes rigorous neuroscience research with double-blind peer review that masks the identity of both the authors and reviewers, minimizing the potential for implicit biases. eNeuro is distinguished by a broader scope and balanced perspective achieved by publishing negative results, failure to replicate or replication studies. New research, computational neuroscience, theories and methods are also published.

About The Society for Neuroscience

The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.

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