Figure 1.
Experimental conditions and trial timeline.
On the left: Example stimuli for the four categories of faces used (fearful and neutral faces with direct and averted gaze). On the right: Illustration of the trial timeline. Each trial started with a fixation point (700–900 ms) followed by the presentation of a face (500 ms), and a blank screen (ISI: 1000–2000 ms) before the next trial started. The participant’s task was to press a button on the occurrence of occasional blue circle targets.
Figure 2.
Illustration of the anatomical segmentation of the amygdala and the hippocampus from the individual T1 MRI scan of a typical subject.
On the left: Amygdala (in green) and hippocampus (in red) segmentation masks obtained with the method of Chupin and coll. (2007) are visualized on a horizontal view of the participant’s anatomical MRI. On the right: Top view of the tessellated surfaces of the amygdala (in green) and the hippocampus (in red) merged with the tessellated cortical surface (obtained with BrainVisa) from the same individual’s MRI scan.
Table 1.
Mean number of sources (±SEM) distributed in the amygdala volume and over the cortical surface across subjects.
Figure 3.
Event-related magnetic fields (ERFs) in response to faces.
On the top: Maps (top-view of the head) of the ERFs at 80, 106 and 144 ms, averaged across all subjects and conditions. Below: Superimposed time courses of the ERFs over the 151 sensors, averaged across all subjects and conditions.
Figure 4.
Amygdala responses to the faces.
A) Time course of the right and left amygdala responses to the fearful (in red) and neutral (in black) faces with direct (plain line) and averted gaze (dashed line). The amygdala activity averaged across the 15 subjects is presented. The time windows where the mean amplitude of amygdala activity was measured are shaded in grey. B) Plots of the effect of emotion and gaze on amygdala activity between 130 and 170 ms and between 190 and 350 ms. On the left: A main effect of the emotion conveyed by the face was observed between 130 and 170 ms. On the middle and right: A main effect of gaze direction qualified by an interaction with emotion and hemisphere was observed between 190 and 350 ms. This reflected a significantly greater response to fearful faces with direct gaze than to fearful faces with averted gaze and to neutral faces with direct gaze in the right amygdala. On every plot, the error bars represent the standard errors of the means across subjects (SEM). C) Correlation between the amygdala activity and the participants’ anxiety score (STAI). This correlation was observed in both time ranges of amygdala activity measurement (130–170 ms and 190–350 ms).
Figure 5.
A) Mean cortical current maps between 130 and 170 ms. The colour-coded activity of cortical dipole sources (in z-score units), averaged across all subjects and conditions, is superimposed on the ventral, back, right and left lateral views of an inflated template brain. Only sources with amplitude above 60% of the scale maximum activity are displayed. B) Time course of cortical source activity in fusiform regions under each experimental condition. The cortical source activity averaged across all subjects over the right and left fusiform clusters respectively (displayed in red on a ventral view of the brain, in a small inset) is presented. C) Time course of cortical source activity in lateral occipital regions under each experimental condition. The cortical source activity averaged across all subjects over the right and left lateral occipital clusters respectively (displayed in red on lateral views of the template brain, in small insets) is presented. The time windows where the mean amplitude of cortical source activity was measured are shaded in grey.