The Relationships of Resting-state Brain Entropy (BEN), Ovarian Hormones and Behavioral Inhibition and Activation Systems (BIS/BAS)

Abstract

Entropy measures the irregularity or complexity of a system. Recent research on brain entropy (BEN) based on resting-state fMRI has provided complementary information to other metrics such as low-frequency fluctuations and cerebral blood flow. It has been established that neural plasticity, both pharmacological and nonpharmacological, as well as brain stimulation can influence BEN. However, it remains unknown whether BEN can reflect the effects of hormones. Furthermore, recent studies have indicated that ovarian hormones influence both the behavioral inhibition and activation systems. In our study, we utilized open-access available data from OpenNeuro to investigate the effects of ovarian hormones on BEN and their impact on BIS/BAS. Our results indicated a negative correlation between progesterone (PROG) and BEN in the frontal-parietal network and limbic system, while BEN showed a significant positive correlation with BAS-drive in the DLPFC. Additionally, a significant negative correlation was observed between PROG and BAS-drive. Further analysis revealed that DLPFC BEN mediates the negative correlation between PROG and BAS-drive. This suggests that PROG reduces BAS-drive by increasing the executive and inhibitory functions of DLPFC. We also analyzed the FC between DLPFC and the whole brain. DLPFC-IPL FC showed a significant positive correlation with BAS-drive, while DLPFC-LOFC FC exhibited a significant negative correlation with BAS-fun-seeking. Moreover, DLPFC-AG FC demonstrated a significant positive correlation with BAS-rewards. These results are consistent with the relationship between executive functions of the frontal-parietal network and impulsivity representation of BAS. Our study is the first to demonstrate that BEN can also reflect the impact of hormones on brain function. Additionally, we identified that the negative correlation between PROG and BAS-drive is mediated by left DLPFC BEN, providing new insights into our understanding of the effects of PROG on the brain and behavior.