Xiaoxiang Wang, Abstract Co-Author: Nothing to Disclose

Jie Tian PhD, Presenter: Nothing to Disclose

Lei Yang, Abstract Co-Author: Nothing to Disclose

To investigate sex differences in lateralized brain activity upon pleasant and unpleasant stimuli by using event-related functional magnetic resonance imaging (fMRI).

16 healthy subjects (8 male and 8 female, mean ages 24.45, SD 3.94) participated in this study (with written informed consent). 135 pictures were selected from International Affective Picture System (IAPS) as standardized emotional visual stimuli, which were carefully matched for arousal, valence and stimulus content. SAM ratings and skin conductance response were used to confirm that these pictures indeed elicit the same level of emotional experience. The stimuli were presented in an event-related design for 500ms and were arranged in a fixed randomized order which counterbalanced across subjects. The interstimulus interval was randomly varied between 7.5 and 10.5s, while a fixation cross was presented. 24 slices of T2* weighted images were acquired with a 3.0T fMRI scanner (Siemens, Germany) by using standard EPI sequence (TR=3000ms, TE=30ms, FOV=192mm, flip angle=90°, matrix size 64*64, 5mm thickness, no gap). Volumes covering the whole brain were obtained. A T1 weighted anatomical MRI was acquired for each subject as well. The functional MRI data were analyzed using SPM2b.

Repeated-measures analysis of variance (ANOVA) was used to assess the statistical significance for fMRI data. Under the same subjective rate of evoked emotion, pleasant-related activations showed greater left-sided in both sexes especially in the lateral frontal cortex and parietal area. In addition, thalamic activation observed in female subjects was not seen in males, whilst male subjects displayed stronger left superior temporal cortex and right amygdala activations that were not found in females. For the unpleasant stimuli, the male subjects demonstrated left inferior frontal, right temporal, left insula and more right amygdala activations; whereas females showed medial prefrontal, anterior and medial cingulate gyrus, and more left amydala activations.

The results suggest that the gender differences do exist in the lateralization of processing visual emotional stimuli, and males show more lateralized activation than females.

Wang, X, Tian, J, Yang, L, Gender Differences in Lateralization of Emotion Processing: An Event-related fMRI Study.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4412453.html