Frontal cerebral oxygenation asymmetry: intersubject variability and dependence on systemic physiology, season, and time of day

Abstract

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.

Individual Differences in Hemodynamic Responses Measured on the Head Due to a Long-Term Stimulation Involving Colored Light Exposure and a Cognitive Task: A SPA-fNIRS Study

“…In particular, the frontal lobe has increasingly become a special region of interest. Frontal cerebral asymmetry of resting-state brain activity has been explained using the approach-withdrawal model, where the higher relative leftward frontal activity is associated with appetitive motivation and approach-related affect (positive affect), while the rightward frontal activity is related to behavioral inhibition and withdrawal-related affect (negative affect) [ 51 , 70 , 71 , 72 ]. In the present study, we show that during the CLE-VFT, red light caused higher oxygenation in the left PFC compared to the right.…”

“…One possible explanation for intersubject-variability of the responses is the fact that the environment and certain situational variables may influence cortical activation response. The dependence of cerebral parameters on several factors, including seasonal changes, time of day, temperature, mood, and chronotype, was investigated in detail in our recent paper [ 51 ]. Briefly, we showed that absolute values of StO 2 during the resting state were not correlated with season and subjects’ mood, but with the time of day and subjects chronotype [ 51 ].…”

“…fNIRS signals were low pass filtered by a robust 2 nd -degree polynomial moving average (RLOESS) with a window length of 3 min. RLOESS filtering with a window length of > 1 min has been used as a smoothing filter in data processing of the fNIRS signals [ 51 , 59 , 60 ]. This method was able to remove high-frequency physiological noise (e.g., heart rate and respiratory rate) of the fNIRS signals.…”

“…Such atypical fNIRS patterns can be attributed to different reasons, including individual differences in vascular regulation and measurement positions, as well as influences from changes in systemic physiology [ 46 , 48 , 49 , 50 ]. The effects of the latter on changes in [O 2 Hb] and [HHb] can be detected by applying systemic physiology augmented functional near-infrared spectroscopy (SPA-fNIRS), which additionally and concurrently with fNIRS measures systemic physiological parameters [ 51 , 52 , 53 ].…”

Prefrontal Asymmetry BCI Neurofeedback Datasets

“…In some experiments, we used a reference epoch to calculate the signal variation, which in some instances required the subject to watch a similar environment to the one used during NF epochs, sometimes also involving a neutral cognitive task, such as counting. It should also be noted that some datasets have considered PFC asymmetry to be zero for the baseline whilst there is evidence of default PFC asymmetry values even in fNIRS (Zohdi et al, 2020) something which was readily captured in EEG experiments (Cavazza et al, 2014) but needs to be redefined on a session or even epoch basis when using hemodynamic signals.…”