Sex differences in brain excitability revealed by concurrent iTBS/fNIRS

Abstract

<p>Sex differences have been claimed an imperative factor in the optimization of psychiatric treatments. Intermittent theta-burst stimulation (iTBS), a patterned form of repetitive <a href="https://www.sciencedirect.com/topics/neuroscience/transcranial-magnetic-stimulation" title="Learn more about transcranial magnetic stimulation from ScienceDirect's AI-generated Topic Pages">transcranial magnetic stimulation</a>, is a promising non-invasive treatment option. Here, we investigated whether the real-time neural response to iTBS differs between men and women, and which mechanisms may mediate these differences. To this end, we capitalized on a concurrent iTBS/functional near-infrared spectroscopy setup over the left <a href="https://www.sciencedirect.com/topics/neuroscience/dorsolateral-prefrontal-cortex" title="Learn more about dorsolateral prefrontal cortex from ScienceDirect's AI-generated Topic Pages">dorsolateral prefrontal cortex</a>, a common clinical target, to test our assumptions. In a series of experiments, we show (1) a biological sex difference in absolute hemoglobin concentrations in the left dorsolateral prefrontal cortex in healthy participants; (2) that this sex difference is amplified by iTBS but not by cognitive tasks; and (3) that the sex difference amplified by iTBS is modulated by stimulation intensity. These results inform future stimulation treatment optimizations towards precision <a href="https://www.sciencedirect.com/topics/neuroscience/psychiatry" title="Learn more about psychiatry from ScienceDirect's AI-generated Topic Pages">psychiatry</a>.<br></p>