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

Figures

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  Figure 1. (A) Localisation of the 22 NIRS probed on the head. The anatomical locations of all NIRS probes, estimated by a three-dimensional digitizer, are summarised in Supplementary Figure S2. (B) experimental protocols about emotionally-charged audiovisual stimulation. The subjective ratings of pleasantness and consciousness were asked immediately after each trial of emotional stimulations as shown by arrows (↓). (C) comparisons of the subjective ratings of pleasantness and consciousness taken after each trial of emotional interventions (comedy, landscape, and horror). †, Significant difference (P < 0.05) among emotional interventions. N. S., not significant difference between emotional interventions.

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  Figure 2. The average changes in heart rate (HR), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), and mean arterial blood pressure (MAP) during an emotionally-charged intervention (comedy, landscape, and horror) in 18 subjects. The cardiovascular variables were analysed by two way repeated measures ANOVA with two main factors of time period (before vs. during) and emotional intervention. The cardiovascular variables were not significantly altered by the time period, suggesting no significant responses to a given emotional intervention. #, Significant difference (P < 0.05) between emotional interventions. N. S., not significant difference between emotional interventions.

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  Figure 3. The time courses of the average changes in prefrontal oxygenated-haemoglobin (Oxy-Hb) over the 22 NIRS channels during each emotionally-charged intervention in 18 subjects. The time course data are shown as mean ± S. E. M. *, Significant response (P < 0.05) from the baseline before intervention. In addition, the symbol of (*) indicates the time point, at which the change in prefrontal Oxy-Hb became significant first in each tracing. The dynamic changes in concentrations of prefrontal deoxygenated-haemoglobin (Deoxy-Hb) during emotionally-charged challenges, as well as Oxy-Hb, are represented in Supplementary Figure S1.

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  Figure 4. (A) The average changes in the Oxy-Hb responses during an emotionally-charged challenge (termed ΔOxy-Hbcomedy, ΔOxy-Hbland, and ΔOxy-Hbhorror) are summarised over the prefrontal 22 locations. The data were statistically analysed by two way repeated measures ANOVA with the factors of emotional intervention and prefrontal location. *, Significant difference (P < 0.05) in the Oxy-Hb response from the baseline. #, Significant differences (P < 0.05) in the Oxy-Hb response between emotional interventions. α, Significant differences (P < 0.05) from ΔOxy-Hbcomedy at the 13th channel. β, Significant differences (P < 0.05) from ΔOxy-Hbcomedy at the 17th channel. γ, Significant differences (P < 0.05) from ΔOxy-Hbhorror at the 9th channel. δ, Significant differences (P < 0.05) from ΔOxy-Hb horror at the 4th channel. By assuming that landscape intervention corresponded to a neutral emotional status and involved non-emotional audiovisual stimulation, the Oxy-Hb responses during landscape intervention were subtracted from those during comedy or horror intervention (termed ΔOxy-Hbcomedy-land and ΔOxy-Hbhorror-land, respectively). (B) the subtracted data were analysed by two way repeated measures…

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  Figure 5. (A) The simultaneous changes in prefrontal Oxy-Hb (NIRS-channel 5), forehead and cheek skin blood flow, hand skin blood flow, and MAP during positively-charged comedy stimulation in 18 subjects. The tracings of the averaged time course data at the three trials of comedy stimulation are superimposed. (B) using the average time course data, the Spearman correlation analysis was conducted between the changes in skin blood flow (cheek, forehead, or hand) or MAP and the Oxy-Hb response obtained in a given NIRS channel. The square values (ϒ2) of the Spearman correlation coefficients are plotted against the NIRS channel number. The data (ϒ2) were statistically analysed by two way repeated measures ANOVA, having the main effect of the peripheral variables (skin blood flow and MAP) and prefrontal location. #, Significant difference (P < 0.05) among the peripheral variables (two way repeated measures ANOVA and posthoc Student-Newman-Keuls test). About forehead skin blood flow, the channels of 1, 4, 5, and 9 [indicated by blue arrows (↓)] had greater ϒ2 (P < 0.05) than the channels of 11, 12, 15–17, and 19–21; about cheek skin blood flow, the channels of 1, 4, and 5 [indicated by black…

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  Figure 6. The simultaneous changes in prefrontal Oxy-Hb, forehead and cheek skin blood flow, and arterial blood pressure (AP) during conversation are represented in one subject. When conversation was made by asking the subjective ratings of pleasantness and consciousness, an increase in the prefrontal Oxy-Hb was observed on both sides, despite no change in the prefrontal Deoxy-Hb (not shown). Facial skin blood flow and AP did not represent substantial changes during conversation.