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Brain processes associated with emotion perception from biological motion have been largely investigated using point-light displays that are devoid of pictorial information and not representative of everyday life. In this study, we investigated the brain signals evoked when perceiving emotions arising from body movements of virtual pedestrians walking in a community environment. Magnetoencephalography was used to record brain activation in 21 healthy young adults discriminating the emotional gaits (neutral, angry, happy) of virtual male/female pedestrians. Event-related responses in the posterior superior temporal sulcus (pSTS), fusiform body area (FBA), extrastriate body area (EBA), amygdala (AMG), and lateral occipital cortex (Occ) were examined. Brain signals were characterized by an early positive peak (P1;∼200ms) and a late positive potential component (LPP) comprising of an early (400-600ms), middle (600-1000ms) and late phase (1000-1500ms). Generalized estimating equations revealed that P1 amplitude was unaffected by emotion and gender of pedestrians. LPP amplitude showed a significant emotion X phase interaction in all regions of interest, revealing i) an emotion-dependent modulation starting in pSTS and Occ, followed by AMG, FBA and EBA, and ii) generally enhanced responses for angry vs. other gait stimuli in the middle LPP phase. LPP also showed a gender X phase interaction in pSTS and Occ, as gender affected the time course of the response to emotional gait. Present findings show that brain activation within areas associated with biological motion, form, and emotion processing is modulated by emotional gait stimuli rendered by virtual simulations representative of everyday life.</div

Main and interaction effects on LPP amplitudes in each ROI.

Statistically significant results are indicated with star symbols, when applicable: *p<0.05, **p<0.01, ***p<0.001. Abbreviations: pSTS, posterior superior temporal sulcus; FBA, fusiform body area; EBA, extrastriate body area; AMG, amygdala; Occ, lateral occipital cortex; df, degree of freedom; Pr, probability.</p

Each trace represents the grand-average waveform with 1 SEM for each emotional gait condition of the female and male pedestrians.

The different colours illustrate the different emotions, i.e., angry (blue), happy (red), and neutral (green). The three separate time intervals of the entire LPP component are marked with vertical lines representing the early (400-600ms), middle (600-1000ms), and late LPP (1000-1500ms) phases. Abbreviation: SEM, standard error of the mean.</p

Fig 6 -

(a) Mean LPP amplitude ± 1 SEM for three separate time windows over 5 ROIs with significant emotion x phase interactions. (blue: angry; red: happy; green: neutral). (b) Mean LPP amplitude of pSTS and Occ with the significant gender x phase interactions (orange: female pedestrian; light blue: male pedestrian). The symbol indicates * p<0.05. ** p<0.01. *** p<0.001. **** p<0.0001. Abbreviation: pSTS, posterior superior temporal sulcus; FBA, fusiform body area; EBA, extrastriate body area; AMG, amygdala; Occ, lateral occipital cortex; SEM, standard error of the mean.</p

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Brain processes associated with emotion perception from biological motion have been largely investigated using point-light displays that are devoid of pictorial information and not representative of everyday life. In this study, we investigated the brain signals evoked when perceiving emotions arising from body movements of virtual pedestrians walking in a community environment. Magnetoencephalography was used to record brain activation in 21 healthy young adults discriminating the emotional gaits (neutral, angry, happy) of virtual male/female pedestrians. Event-related responses in the posterior superior temporal sulcus (pSTS), fusiform body area (FBA), extrastriate body area (EBA), amygdala (AMG), and lateral occipital cortex (Occ) were examined. Brain signals were characterized by an early positive peak (P1;∼200ms) and a late positive potential component (LPP) comprising of an early (400-600ms), middle (600-1000ms) and late phase (1000-1500ms). Generalized estimating equations revealed that P1 amplitude was unaffected by emotion and gender of pedestrians. LPP amplitude showed a significant emotion X phase interaction in all regions of interest, revealing i) an emotion-dependent modulation starting in pSTS and Occ, followed by AMG, FBA and EBA, and ii) generally enhanced responses for angry vs. other gait stimuli in the middle LPP phase. LPP also showed a gender X phase interaction in pSTS and Occ, as gender affected the time course of the response to emotional gait. Present findings show that brain activation within areas associated with biological motion, form, and emotion processing is modulated by emotional gait stimuli rendered by virtual simulations representative of everyday life.</div

Fig 1 -

(a) Example of the virtual environment with a metro station background and an approaching virtual pedestrian walking with an emotional gait. The black dotted lines (not visible to the participant) indicate the three possible pedestrian trajectories. (b) The experimental setup, including the rear-projection display and the MEG instrument. (c) One participant with electrodermal sensors measuring heartbeats and eye movements, as well as 3D glasses. They were instructed to hold the response box with both hands to avoid MEG signal contamination induced by muscle tension. Reprinted from [47], under a CC BY license, with permission from ProQuest Dissertations & Theses (McGill University), original copyright Yu-Tzu Wu 2022.</p

Mean proportion of correct responses (± 1SD) in the emotion identification task for each emotional gait condition (blue: Angry; red: Happy; green: Neutral) for the female (left column) and male virtual pedestrian (right column).

Statistically significant main and interaction effects are indicated, as applicable. Likewise, post-hoc comparisons that were statically significant are also illustrated (* p<0.05. ** p<0.01. *** p<0.001. **** p<0.0001).</p

Timeline of an experimental trial with an example of a male pedestrian approaching from the left.

Initially, the sliding door was closed, and the pedestrian was not visible to the participant (left panel). Then, the door opened and the observed would see an approaching pedestrian with an emotional gait pattern (middle panel). At the end of the trial (right panel), a display with three response options was overlaid to the virtual environment to request participants to provide responses. Abbreviation: ISI, inter-stimulus interval. Reprinted from [47], under a CC BY license, with permission from ProQuest Dissertations & Theses (McGill University), original copyright Yu-Tzu Wu 2022.</p

S3 File -

Brain processes associated with emotion perception from biological motion have been largely investigated using point-light displays that are devoid of pictorial information and not representative of everyday life. In this study, we investigated the brain signals evoked when perceiving emotions arising from body movements of virtual pedestrians walking in a community environment. Magnetoencephalography was used to record brain activation in 21 healthy young adults discriminating the emotional gaits (neutral, angry, happy) of virtual male/female pedestrians. Event-related responses in the posterior superior temporal sulcus (pSTS), fusiform body area (FBA), extrastriate body area (EBA), amygdala (AMG), and lateral occipital cortex (Occ) were examined. Brain signals were characterized by an early positive peak (P1;∼200ms) and a late positive potential component (LPP) comprising of an early (400-600ms), middle (600-1000ms) and late phase (1000-1500ms). Generalized estimating equations revealed that P1 amplitude was unaffected by emotion and gender of pedestrians. LPP amplitude showed a significant emotion X phase interaction in all regions of interest, revealing i) an emotion-dependent modulation starting in pSTS and Occ, followed by AMG, FBA and EBA, and ii) generally enhanced responses for angry vs. other gait stimuli in the middle LPP phase. LPP also showed a gender X phase interaction in pSTS and Occ, as gender affected the time course of the response to emotional gait. Present findings show that brain activation within areas associated with biological motion, form, and emotion processing is modulated by emotional gait stimuli rendered by virtual simulations representative of everyday life.</div

Contrasts of emotional (upper: Angry vs neutral; bottom: Happy vs neutral) gait patterns showed stronger and more widespread emotion-specific activation (left: Medial view; right: Superior view), and the ROIs were indicated in the activation areas.

The colour bars on the right indicate the grading of the z-score. Note that the scale of angry vs. neutral (top-right) was modified to match the values. The obtained results were averaged across time interval corresponding to early LPP (400-600ms), middle LPP (600–1,000ms), and late LPP (1,000–1,500ms), respectively. Abbreviation: pSTS, posterior superior temporal sulcus; FBA, fusiform body area; EBA, extrastriate body area; AMG, amygdala; Occ, lateral occipital cortex.</p