Transcutaneous Auricular Vagus Nerve Stimulation Facilitates Cortical Arousal and Alertness

Figures

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  Figure 1. Experimental procedure and behavioral results. (a) Description of the experimental procedure; (b) Description of the single trial procedure in the dot-probe task; (c) Schematic of the taVNS stimulator and the stimulating sites; (d) The comparison of RT difference (post–pre) for left- and right-hand responses between the two groups. * p < 0.05; taVNS, transcutaneous auricular vagus nerve stimulation; RT, reaction time; ns, non-significant.

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  Figure 2. The high-α oscillation PSD under the close-eye resting state. (a) PSD topographies in the pre-test and post-test phases and the post–pre PSD difference topographies of high-α oscillations for the taVNS group and control group; (b) Topography of the t-value obtained from independent sample t-tests at each electrode for high-α oscillation PSD difference; (c) High-α oscillation PSD difference for the taVNS group and the control group; (d) Group average spectra and their post–pre differences at the C3 and CP5 electrodes for the taVNS group and the control group. Red asterisks in (b) represents significant differences between the taVNS group and the control group; the shadow region in (d, right panel) represents the frequency range of high-α oscillations; *** p ≤ 0.001.

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  Figure 3. Microstate analysis procedure and mean duration difference of each microstate under the close-eye resting state. (a) EEG data after preprocessing; (b) GFP of signals marked by red dashed box in (a) and topographies at the latencies of GFP peaks; (c) Four microstates (i.e., microstates A–D) obtained by integrating all subjects’ EEG data after AAHC and sorting; (d) Single subject sequence obtained by back fitting from global microstate templates; (e) Mean duration difference for each microstate (i.e., microstates A–D, respectively, marked in different colors) under the close-eye resting state was extracted and calculated by single subject sequence. GFP, global field power; AAHC, atomize and agglomerate hierarchical clustering. * p < 0.05.

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  Figure 4. Partial correlation between the RT difference and the PSD difference of high-α oscillations in the taVNS group under the close-eye resting state. ** p < 0.01.