Sex-related differences in working memory for orientations: Analysis of distributed EEG sources model

A group of 31 healthy young adults (16 males and 15 females) performed two working memory tasks (WM): they were asked to 1) compare the orientations of sequentially presented sample and test gratings and 2) determine the direction of rotation of the test grating relative to the sample one. 128-channel EEG was registered. A multivariate analysis of distributed dipole activity was performed for the stage of comparison (in the interval of 50-350 ms after the test stimulus onset). Statistically significant sex related differences were revealed in the topography of cortical activity related to the comparison of the sample and test gratings. The differences were observed bilaterally in the occipital, parietal and temporal regions and, to a lesser extent, in the frontal cortex. The “males > females” contrasts were significant for the dipole activity of the posterior areas (occipital, parietal and temporal), while the "females > males" contrasts were significant in the structures of the frontal cortex. The obtained data confirm that neural networks involved in working memory for orientations differ between males and females. Specifically, males demonstrate a greater involvement of the posterior cortical areas, while in females the frontal cortex is more involved. Highlights Neural networks involved in orientation working memory differ between males and females. When performing orientation working memory, males demonstrate a greater activation of the caudal cortical areas, while in females the frontal cortex is more involved.