The control of strong emotional reactions in response to affective pictures by high harm avoidand females during an fMRI experiment.

Introduction

In our previous study [1], in response to aversive stimuli less amygdala activity was found in correlation to the personality trait 'Harm Avoidance' (HA) in females while watching passively to blocks with positive or negative affective pictures. However, high HA means stronger negative reactions and paying more attention towards aversive stimuli, resulting in more amygdala activity [2]. To explain this discrepancy, we hypothesized that our volunteers anticipated to the negative stimuli either by shifting their attention away from the pictures or by suppressing their emotional reaction. In an attempt to test this hypothesis, we repeated the fMRI experiment but now we restricted the possibility to anticipate by presenting the pictures in random order and asking to evaluate the valence of the shown pictures.

Materials and methods

We included 33 non-depressed female volunteers (22±3 years) and quantified their personality with the temperament and character inventory (TCI). During the MRI, they had to evaluate pictures of happy smiling baby faces as positive and unhappy crying baby faces with a severe dermatological condition as negative affective pictures. The associated brain activity was measured with a standard EPI sequence (dynamic resolution: 3s) at a 1.5T MRI scanner. Based on the individual response maps and for each affective condition, we performed a multiple regression analysis with all personality traits and age as regressors on circular ROI's (radius: 5mm) defined on the maximum response in the amygdalae, subregions of the PFC known to regulate the amygdalae response and the visual cortex.

Results

Using a significance threshold of p
Discution and conclusions

Although statistically weak, restricting the posibility to anticipate to the presented stimuli seems to result in the expected behavior for the amygdala activity in relation to HA (figure 3). In an attempt to control the emotional reaction, more PFC activity was seen. In conclusion, the high harm avoidand females in our experiments tried to avoid or suppress strong emotional reactions to negative stimuli.

References

[1] Baeken C. et al. (2009): Brain Research; 1296:94-103
[2] Most S. et al. (2006): NeuroImage; 31:1016-1027