Neuropsychologia
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A recent study showed that motor imagery was compromised after right congenital hemiparesis. In that study, posture of the displayed stimuli and the actual posture of the hand making the response were incongruent. Ample evidence exists that such an incongruency may negatively influence laterality judgements in a mental rotation task. ⋯ However, reaction times for the participants with hemiparesis were consistently slower compared to controls and no asymmetry in responding between the affected and less-affected hand was found, suggesting a visual imagery strategy. Collectively, these results suggest that the ability to mentally rotate stimuli is still intact in right hemiparesis. The results are discussed in relation to two strategies that may have been used to solve the task: visual imagery and motor imagery.
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Recent observations indicate that sex and level of steroid hormones may influence cortical networks associated with specific cognitive functions, in particular visuo-spatial abilities. The present study probed the influence of sex, menstrual cycle, and sex steroid hormones on 3D mental rotation and brain function using 3-T fMRI. Twelve healthy women and 12 men were investigated. ⋯ Our study provides evidence that fMRI-related activity during performance of cognitive tasks varies across sex and phases of the menstrual cycle. The variation might be partly explained by better task performance in men, but our results indicate that further explanations like basic neuronal or neurovascular effects modulated by steroid hormones must be considered. Both estradiol and testosterone levels may influence fMRI signals of cognitive tasks, which should affect selection of subjects for future fMRI studies.