Sex-related differences in task switching: An fMRI study

Abstract

Executive functions are the important human ability to program, regulate, and control the implementation of various cognitive processes, such as voluntary task switching. However, sex-related features of this process have not been characterized in sufficient detail. These distinctive features were studied using functional magnetic resonance imaging (fMRI) and neuropsychological examination. Seventy healthy subjects 21–48 years of age (36 men and 34 women) were involved in the study. During an fMRI experiment, the subjects had to shift their attention between two tasks (classifying figures according to their form or number). In neuropsychological examination participants completed a series of visual attention, task switching, and memory tests. The fMRI study revealed that a neuronal network controlling task switching in women includes the dorsolateral prefrontal and inferior parietal cortical areas, as well as the secondary areas of the visual cortex in the left hemisphere (LH) and the right hemisphere (RH), and cortical areas of the left and right hemispheres of the cerebellum. The same areas were activated in men and additional sites of activation were detected in the supplementary motor area, right insula, and left thalamus. Comparison of the groups of men and women revealed significantly stronger activation of the prefrontal areas in both LH and RH, the left parietal lobe, and the right insula in men, and moreover activation of the supplementary motor area was observed in men but not in women. Neuropsychological testing showed that men took significantly more time to perform tasks requiring task switching, searching for stimuli, and arranging them. The data obtained indicate differences in the organization of visual task switching processes in men and women.