Significance: Our study reveals that frontal cerebral oxygenation asymmetry (FCOA), i.e. a difference in the oxygenation between the right and left prefrontal cortex (PFC), is a real phenomenon in healthy human subjects at rest. Aim: To investigate FCOA, we performed a study with 134 healthy right-handed subjects with the systemic physiology augmented functional near infrared spectroscopy (SPA-fNIRS) approach. Approach: Subjects were measured 2 to 4 times on different days resulting in an unprecedented number of 518 single measurements of the absolute values of tissue oxygen saturation ( StO 2 ) and total hemoglobin concentration ([tHb]) of the right and left PFC. Measurements were performed with frequency-domain functional near-infrared spectroscopy. In addition, the cardiorespiratory parameters were measured simultaneously. Results: We found that (i) subjects showed an FCOA (higher StO 2 on the right PFC), but not for tHb; (ii) intrasubject variability was excellent for both StO 2 and tHb, and fair for FCOA; (iii) StO 2 correlated significantly with blood CO 2 concentration, [tHb] with heart rate, respiration rate (RR), and the pulse-respiration quotient (PRQ), and FCOA with RR and PRQ; (iv) FCOA and StO 2 were dependent on season and time of day, respectively; (v) FCOA was negatively correlated with the room temperature; and (vi) StO 2 and tHb were not correlated with the subjects mood but with their chronotype, whereas FCOA was not dependent on the chronotype. Conclusion: Our study demonstrates that FCOA is real, and it provides unique insights into this remarkable phenomenon.

中文翻译：

---

额叶脑氧合不对称：个体间的变异性和对全身生理学、季节和一天中时间的依赖性。


意义：我们的研究表明，额叶脑氧合不对称（FCOA），即左右前额皮质（PFC）之间的氧合差异，是健康人体受试者在休息时的真实现象。目的：为了研究 FCOA，我们采用系统生理学增强功能近红外光谱 (SPA-fNIRS) 方法对 134 名健康的右手受试者进行了一项研究。方法：在不同的日子对受试者进行 2 至 4 次测量，从而对左右 PFC 的组织氧饱和度 (StO 2 ) 和总血红蛋白浓度 ([tHb]) 的绝对值进行了前所未有的 518 次单次测量。使用频域功能近红外光谱进行测量。此外，同时测量心肺参数。结果：我们发现 (i) 受试者表现出 FCOA（右侧 PFC 较高的 StO 2），但 tHb 没有表现出； (ii) StO 2 和 tHb 的受试者内变异性都非常好，而 FCOA 的受试者内变异性则相当； (iii) StO 2 与血液CO 2 浓度显着相关，[tHb]与心率、呼吸频率(RR)和脉搏呼吸商(PRQ)显着相关，FCOA与RR和PRQ显着相关； (iv) FCOA 和 StO 2 分别取决于季节和一天中的时间； (v) FCOA与室温呈负相关； (vi) StO 2 和 tHb 与受试者的情绪无关，但与他们的时间类型相关，而 FCOA 不依赖于时间类型。结论：我们的研究表明 FCOA 是真实的，并且它为这一非凡现象提供了独特的见解。