Would frontal midline theta indicate cognitive changes induced by non-invasive brain stimulation? A mini review

• Published in: Frontiers in human neuroscience Vol. 17; p. 1116890
• Main Authors: Nakamura-Palacios, Ester Miyuki, Falçoni Júnior, Aldren Thomazini, Anders, Quézia Silva, de Paula, Lucas Dos Santos Pereira, Zottele, Mariana Zamprogno, Ronchete, Christiane Furlan, Lirio, Pedro Henrique Cassaro
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 14-07-2023; Frontiers Media S.A
• Subjects: Anxiety; Behavior; Cognition & reasoning; Cognitive ability; cognitive control; Cortex (cingulate); Cortex (frontal); executive functions (EFs); frontal midline theta (FM-theta); Memory; Mental disorders; Neuroscience; non-invasive brain stimulation (NIBS); Prefrontal cortex; Short term memory; transcranial direct current stimulation (tDCS); Transcranial magnetic stimulation; working memory (WM); executive functions (EFs); cognitive control; working memory (WM); transcranial alternate current stimulation (tACS); transcranial magnetic stimulation (TMS); frontal midline theta (FM-theta); non-invasive brain stimulation (NIBS); transcranial direct current stimulation (tDCS)
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2023.1116890

To the best of our knowledge, neurophysiological markers indicating changes induced by non-invasive brain stimulation (NIBS) on cognitive performance, especially one of the most investigated under these procedures, working memory (WM), are little known. Here, we will briefly introduce frontal midline theta (FM-theta) oscillation (4-8 Hz) as a possible indicator for NIBS effects on WM processing. Electrophysiological recordings of FM-theta oscillation seem to originate in the medial frontal cortex and the anterior cingulate cortex, but they may be driven more subcortically. FM-theta has been acknowledged to occur during memory and emotion processing, and it has been related to WM and sustained attention. It mainly occurs in the frontal region during a delay period, in which specific information previously shown is no longer perceived and must be manipulated to allow a later (delayed) response and observed in posterior regions during information maintenance. Most NIBS studies investigating effects on cognitive performance have used n-back tasks that mix manipulation and maintenance processes. Thus, if considering FM-theta as a potential neurophysiological indicator for NIBS effects on different WM components, adequate cognitive tasks should be considered to better address the complexity of WM processing. Future research should also evaluate the potential use of FM-theta as an index of the therapeutic effects of NIBS intervention on neuropsychiatric disorders, especially those involving the ventral medial prefrontal cortex and cognitive dysfunctions.