Altered Dorsolateral Prefrontal Activation in Response to Verbal Fluency Task and Whole-Brain Resting-State...

The study aims to investigate changes in brain activity during the verbal fluency task (VFT) and resting-state brain network features in patients with acute carbon monoxide (CO) poisoning using functional near-infrared spectroscopy (fNIRS). We also explored the relationship between cognitive function and the fNIRS-derived features of oxyhemoglobin (Oxy-Hb) concentration curves in the cerebral cortex.

We first performed a cross-sectional study in patients with acute CO poisoning and healthy controls between January and December 2024. The fNIRS-derived features (centroid and mean) of the Oxy-Hb curve in the frontotemporal cortex during VFT were compared between CO poisoning patients and healthy controls. The functional connectivity of brain networks in patients with acute CO poisoning during the resting state was also analyzed to identify factors representing network features of the cerebral cortex in patients with acute CO poisoning. We then performed a prospective cohort study to compare the brain activity changes after the hyperbaric oxygen therapy in patients with acute CO poisoning.

The study included 29 patients with CO poisoning and 28 healthy controls. During the VFT, the centroid of the Oxy-Hb curve in Brodmann area 46 was significantly lower in CO poisoning patients compared to the healthy controls (p < 0.01). The centroid and mean values of Brodmann area 46 exhibited a significant positive correlation with Mini-Mental State Examination scores, while the mean value was positively correlated with VFT scores. Mean values in Brodmann areas 11 and 38 were significantly lower in CO poisoning patients (both p < 0.05). The average whole-brain resting-state functional connectivity strength (FCS) was significantly lower in CO poisoning patients compared to healthy controls (p < 0.05), with significant differences in FCS observed in 39 pairs of channels (p < 0.01). Twenty sessions of hyperbaric oxygen therapy resulted in improved FCS (p < 0.01) and centroid values for the Oxy-Hb curve in the left dorsolateral prefrontal cortex during the VFT (p < 0.05).

The centroid values of the Oxy-Hb curve in the left dorsolateral prefrontal cortex during the VFT, along with the average whole-brain resting-state FCS, potentially could serve as characteristic indicators of brain function in patients with acute CO poisoning.