Exploring the predictive power of iTBS induced prefrontal excitability using concurrent TBS/fNIRS

Area of Science:

• Neuroscience
• Cognitive Science
• Neuromodulation

Background:

• The impact of single-session intermittent theta-burst stimulation (iTBS) on dorsolateral prefrontal cortex (DLPFC) function is not fully understood.
• The clinical utility of predicting DLPFC function based on iTBS-induced excitability remains unexplored.

Purpose of the Study:

• To investigate the immediate effects of a single iTBS session on DLPFC function and cortical excitability.
• To determine if iTBS-induced prefrontal cortical excitability can predict working memory performance.

Main Methods:

• A randomized, sham-controlled, crossover study involving 30 healthy participants.
• Concurrent iTBS and functional near-infrared spectroscopy (fNIRS) were used to measure prefrontal hemoglobin concentrations.
• Working memory was assessed using the 3-back task before and after stimulation.

Main Results:

• No significant difference in 3-back task performance between active and sham iTBS.
• A significant decrease in iTBS-induced oxygen-hemoglobin (HbO) change in the active group compared to sham.
• iTBS-induced HbO changes did not significantly predict working memory performance at any timepoint.

Conclusions:

• A single iTBS session to the left DLPFC induces immediate cortical excitability changes but does not enhance working memory compared to sham.
• iTBS-induced prefrontal excitability does not predict subsequent working memory performance after a single session.
• Further research with larger sample sizes is needed to explore iTBS-induced excitability as a potential imaging marker for clinical treatment response.