Sex differences in brain excitability revealed by concurrent iTBS/fNIRS

Asian J Psychiatr. 2024 Jun:96:104043. doi: 10.1016/j.ajp.2024.104043. Epub 2024 Apr 3.

Abstract

Sex differences have been claimed an imperative factor in the optimization of psychiatric treatments. Intermittent theta-burst stimulation (iTBS), a patterned form of repetitive transcranial magnetic stimulation, 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 dorsolateral prefrontal cortex, 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 psychiatry.

Keywords: Intermittent theta-burst stimulation; Real-time cortical response; Sex differences.

MeSH terms

  • Adult
  • Dorsolateral Prefrontal Cortex* / physiology
  • Female
  • Humans
  • Male
  • Sex Characteristics
  • Spectroscopy, Near-Infrared* / methods
  • Transcranial Magnetic Stimulation* / methods
  • Young Adult