Methylphenidate-mediated reduction in prefrontal hemodynamic responses to working memory task: a functional...

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Functional near-infrared spectroscopy (fNIRS) offers non-invasive bedside monitoring of cerebral metabolism.
• fNIRS has potential for assessing pharmacological treatment efficacy.
• Methylphenidate (MP) is a stimulant medication with known cognitive effects.

Purpose of the Study:

• To investigate the cognitive effects of methylphenidate (MP) on prefrontal function in healthy subjects using fNIRS.
• To assess changes in cerebral oxygenation during working memory tasks after MP administration.
• To correlate fNIRS findings with cognitive performance improvements.

Main Methods:

• A double-blind, placebo-controlled crossover study involving 13 healthy subjects.
• Administration of a single oral dose of MP (20 mg) or placebo.
• Performance of 0-back and 2-back working memory tasks with two-channel fNIRS monitoring of prefrontal oxyhemoglobin and deoxyhemoglobin.

Main Results:

• Subjects showed significantly improved performance (more correct, fewer missed responses) on the 2-back task after MP compared to placebo.
• MP treatment led to a significant decrease in oxyhemoglobin in the right frontal region during the 2-back task.
• No significant differences in deoxyhemoglobin or total hemoglobin were observed between MP and placebo conditions for either task.

Conclusions:

• The findings suggest MP enhances cognitive performance, potentially by reducing lateral prefrontal activity.
• fNIRS can detect MP-induced changes in prefrontal hemodynamics related to cognitive task performance.
• These results align with prior positron emission tomography studies on MP's effects on brain activity.