Characteristics of Cerebral Blood Flow during Working Memory Tasks - Comparison of the follicular and luteal phases in females and males

Abstract

In this study, we aimed to clarify the characteristics of cerebral blood flow during the N-back task for males and for females in the follicular and luteal phases. Near infrared spectroscopy (NIRS) was used to measure Oxyhemoglobin (Oxy-Hb) in the prefrontal cortex during the N-back task. In the analysis, the prefrontal cortex was divided into right and left regions, and the integrated Oxy-Hb value, center of gravity value, and activation rate (initial activation) in the first 5 seconds of the task were calculated for each region. The percentage of correct responses to the N-back task was also calculated. Differences in each representative value among the three groups (follicular phase, luteal phase, and male) were examined. The task correct response rate was lowest in the luteal phase group for males and the luteal phase group (p<.05) and in the follicular phase group and the luteal phase group (p<.05). There were no significant differences between groups in integral and center-of-gravity values, and there were significant differences between groups in the initial activation of CH10-13 (left area) during the 2-back task (p<.05), with the lowest in the luteal phase group among males (p<.05), follicular phase group (p<.05) and luteal phase group (p<.05). A decrease in working memory is suggested in luteal phase women. This may be due to the presence of women with premenstrual syndrome symptoms or to sex hormone effects.