Alpha/beta-gamma decoupling in methylphenidate medicated ADHD patients

Nowell Zammit; Richard Muscat

doi:10.3389/fnins.2023.1267901

Alpha/beta-gamma decoupling in methylphenidate medicated ADHD patients

Front Neurosci. 2023 Sep 29:17:1267901. doi: 10.3389/fnins.2023.1267901. eCollection 2023.

Authors

Nowell Zammit¹, Richard Muscat^{1

2}

Affiliations

¹ Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta.
² Department of Physiology and Biochemistry, University of Malta, Msida, Malta.

Abstract

There is much interest to understand how different neural rhythms function, interact and are regulated. Here, we focus on WM delay gamma to investigate its coupling with alpha/beta rhythms and its neuromodulation by methylphenidate. We address this through the use of human EEG conducted in healthy and ADHD subjects which revealed ADHD-specific electrophysiological deficits and MPH-induced normalization of gamma amplitude and its coupling with alpha/beta rhythms. Decreased alpha/beta-gamma coupling is known to facilitate memory representations via disinhibition of gamma ensembles coding the maintained stimuli. Here, we present EEG evidence which suggests that these dynamics are sensitive to catecholaminergic neuromodulation. MPH decreased alpha/beta-gamma coupling and this was related to the increase in delay-relevant gamma activity evoked by the same drug. These results add further to the neuromodulatory findings that reflect an electrophysiological dimension to the well-known link between WM delay and catecholaminergic transmission.

Keywords: ADHD; EEG; coupling; methylphenidate; neural oscillations; working memory.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the University of Malta.