Prefrontal oxygenation correlates to the responses in facial skin blood flows during exposure to pleasantly charged movie

Abstract

Our laboratory reported that facial skin blood flow may serve as a sensitive tool to assess an emotional status. Cerebral neural correlates during emotional interventions should be sought in relation to the changes in facial skin blood flow. To test the hypothesis that prefrontal activity has positive relation to the changes in facial skin blood flow during emotionally charged stimulation, we examined the dynamic changes in prefrontal oxygenation (with near‐infrared spectroscopy) and facial skin blood flows (with two‐dimensional laser speckle and Doppler flowmetry) during emotionally charged audiovisual challenges for 2 min (by viewing comedy, landscape, and horror movie) in 14 subjects. Hand skin blood flow and systemic hemodynamics were simultaneously measured. The extents of pleasantness and consciousness for each emotional stimulus were estimated by subjective rating from −5 (the most unpleasant; the most unconscious) to +5 (the most pleasant; the most conscious). Positively charged emotional stimulation (comedy) simultaneously decreased (P < 0.05) prefrontal oxygenation and facial skin blood flow, whereas negatively charged (horror) or neutral (landscape) emotional stimulation did not alter or slightly decreased them. Any of hand skin blood flow and systemic cardiovascular variables did not change significantly during positively charged emotional stimulation. The changes in prefrontal oxygenation had a highly positive correlation with the changes in facial skin blood flow without altering perfusion pressure, and they were inversely correlated with the subjective rating of pleasantness. The reduction in prefrontal oxygenation during positively charged emotional stimulation suggests a decrease in prefrontal neural activity, which may in turn elicit neurally mediated vasoconstriction of facial skin blood vessels.

Deactivation of the prefrontal cortex during exposure to pleasantly-charged emotional challenge

“…However, we found that prefrontal oxygenation was augmented during conversation without changing forehead skin blood flow (Fig. 6 ), in agreement with our previous study 29 . Such dissociation between the responses in prefrontal oxygenation and forehead skin blood flow has been recognised during a cognitive Stroop test and voluntary exercise 34 – 36 .…”

“…We have reported that facial skin blood flow decreases during positively-charged emotional stimulation and may serve as a more sensitive tool to assess an emotional or mood status in humans 28 . Furthermore, we have revealed that the decrease in facial skin blood flow is closely correlated to the responses in prefrontal oxygenation measured with 2-channel NIRS probes attached on the forehead 29 . However, the spatial distribution of the dynamic changes in oxygenation over the PFC remained to be solved.…”

“…The other was near-infrared spectroscopy (NIRS), which is able to detect the dynamic changes in concentration of regional oxygenated haemoglobin (Oxy-Hb) as index of cortical activity in a mobile condition. With two-channel NIRS probes attached on the forehead, we have recently revealed that positively-charged audiovisual stimulation can evoke a reduction in prefrontal oxygenation, which may imply a decrease in regional CBF and thereby may reflect reduced activity in the PFC 29 . However, since the spatial distribution of the Oxy-Hb response has not been examined, it was important for understating of neural mechanisms within the PFC to determine detail location of the prefrontal oxygenation response during emotionally-charged interventions (defined as audiovisual stimulation in this study).…”

Data-driven analysis of facial thermal responses to an emotional movie reveals consistent stimulus-locked physiological changes

“…We demonstrated that facial thermal response is negatively correlated to this happy state. Anticorrelation of thermal responses with positive emotions has been previously demonstrated in a controlled paradigm (Matsukawa et al, 2017). However contrasting results have also been found (Zenju et al, 2004) but which have used static images as stimuli.…”

“…Here we investigate whether such shared responses are present in various physiological signals (heart rate metrics, skin conductance and thermal responses). Furthermore, reports also suggest the differentiating role of facial temperature in emotional valence [(Matsukawa et al, 2017;Zenju, Nozawa, Tanaka, & Ide, 2004) but also see (Kosonogov et al, 2017;Salazar-López et al, 2015)]. Hence, we also sought to investigate whether there is an association between emotion characteristics of the movie and facial thermal changes.…”