Method for Individual Assessment of Human Cerebral Cortex Activity by a Combined Use of Magnetic Resonance Spectroscopy of Glutamate and BOLD Signal Method

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Aleksandr D. Korotkov^1,a*, Artem D. Myznikov¹, Ilya M. Krasnov¹, Mikhail D. Didur¹, Denis V. Cherednichenko¹, and Maxim V. Kireev²

¹N. P. Bechtereva Institute of the Human Brain, Russian Academy of Sciences, 197022 St. Petersburg, Russia

²Institute for Cognitive Studies, Saint Petersburg State University, 199004 St. Petersburg, Russia

^* To whom correspondence should be addressed.

Received: January 21, 2026; Revised: March 30, 2026; Accepted: March 31, 2026

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Modern magnetic resonance imaging (MRI) methods enable individualized assessment of both functional brain activity and neurochemical composition. Functional magnetic resonance imaging (fMRI) allows evaluation of brain activity at rest and during task performance, while magnetic resonance spectroscopy (MRS) provides measurements of key metabolites such as choline, N-acetylaspartate, creatine, lactate, lipids, alanine, glutamine and glutamate, GABA, and myo-inositol. These approaches are widely used in both fundamental brain research and diagnostic studies. However, existing literature lacks methods for directly comparing these individual assessments, which is essential for investigating relationships between metabolite levels and brain activity. Here, we present a method for aligning individual fMRI and MRS data. Using this approach, we demonstrated a neurophysiological phenomenon in which the functional connectivity between brain regions increases while overall functional activity decreases during task performance.

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KEY WORDS: glutamate, fMRI, BOLD signal, connectomics, functional connectivity, magnetic resonance spectroscopy

DOI: 10.1134/S0006297926600213

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