| Abstract No.: | A-C1112 |
| Country: | Canada |
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| Title: | SEX DIFFERENCES IN FRONTAL AND PARIETAL CORTEX ACTIVATIONS DURING MENTAL ROTATION BY SCHIZOPHRENIA PATIENTS AND HEALTHY CONTROLS. |
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| Authors/Affiliations: | 2 Jose Jimenez*; 1 Adham Mancini-Marie; 1 Melissa Rinaldi; 1 Adrianna Mendrek;
1 1Department of Psychiatry, Fernand-Seguin Research Center, Louis-H Lafontaine Hospital, University of Montreal, Montreal; 2 Department of Psychiatry, Fernand-Seguin Research Center, Louis-H Lafontaine Hospital, University of Montreal, QC, Canada
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| Content: | Introduction: Several studies have shown that men perform better than women on three-dimensional (3D) mental rotation tasks (Linn and Petersen 1985; Voyer et al. 1995). Moreover, the performance on these tasks has been associated with increased parietal cortex activations in men and increased frontal activations in women (Jordan et al., 2003; Hugdahl et al., 2006). Investigations of visuo-spatial abilities and other cognitive functions in schizophrenia have produced inconsistent results. Nevertheless, based on our recent fMRI study suggesting reversal of normal sexual dimorphism in brain function of schizophrenia patients during processing of emotional stimuli (Mendrek et al., 2007), we hypothesized existence of similar phenomena in frontal and parietal cortex during performance of a mental rotation task.
Methods: 16 men (SZ-M) and 7 women (SZ-W) fulfilling DSM-IV criteria for schizophrenia were compared to 14 healthy men (HM) and 7 healthy women (HW) during performance of a classic mental rotation task adopted from Sheppard & Meltzer (1971). In this task subjects mentally rotated and compared pairs of 3D figures to determine whether the stimuli were identical or mirror-images with a control task that used identical stimuli, but required no mental rotation. BOLD echoplanar images were acquired on a 3Tesla Siemens TRIO system (Voxel size 3.5 x 3.5 x 3.5 mm, TR=3000ms, TE=30ms, slices=41). Analyses were performed using SPM5 (UK Wellcome Institute) using parietal and lateral frontal masks with Voxel-Based-Morphometry (VBM) and Anatomical Automated Labeling (aal), only corrected p-values, voxels≥5 and z-scores≥3.00 were considered.
Results: There were no significant differences between men and women in age, handedness, schizophrenia symptoms, or antipsychotic chlorpromazine equivalence. Behaviorally, no significant differences were found between men and women in both clinical groups with regards to the mental rotation task performance. In terms of cerebral function, random effects analyses revealed significant bilateral activation in the superior parietal (BA7) and right inferior parietal (BA40) cortex in HM and diminished, though detectable activations in the right precuneus (BA7) and right superior parietal cortex (BA7) in SZ-W. HW and SZ-M showed no detectable activations. Activations in the frontal cortex were significant only in the group of HM in the bilateral superior frontal and right middle frontal cortex.
Conclusions: To our knowledge this is the first study to investigate sex differences in brain function during mental rotation in schizophrenia. Consistently with some previous reports we found mainly parietal activations in HM. Interestingly, in schizophrenia the pattern of sex differences was somewhat reversed with SZ-W displaying male-like, though diminished, activation pattern similar to HM, and SZ-M resembling HW with no significant activations in the parietal region. In order to fully understand the implications of these preliminary findings we are in the process if testing a greater number of subjects and correlating the results with estrogen and testosterone levels.
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