Sex Differences in Neural Correlates of Inhibitory Control

This chapter reviews the current evidence for sex differences in neural function underlying inhibitory control. Specifically, the chapter focuses on sex differences in functional magnetic resonance imaging (fMRI) measures of brain engagement during response inhibition on stop signal and go/no-go tasks. Sex differences appear to exist in these measures, but the direction of effect depends on the population studied, the task used, and whether successful or unsuccessful inhibition is examined. For successful inhibition, healthy men typically show greater brain engagement in right frontal regions typically implicated in inhibitory control (e.g., inferior frontal gyrus and supplementary motor area) than women, especially when performing the stop signal task. However, in younger populations or when controlling for the effects of age, women tend to show greater brain engagement than men, especially when performing the go/no-go task. For unsuccessful inhibition, women tend to show greater brain engagement compared to men in the anterior cingulate cortex and thalamus. Taken together, findings suggest that sex differences in neural responses to response inhibition depend on the specific type of inhibition studied and on whether the inhibition is successful or unsuccessful. Men exhibit greater response during successful inhibition, whereas women consistently display greater neural responses during unsuccessful inhibition. The chapter highlights limitations and gaps in this research to date, including a lack of consideration of the role of sex hormones and menstrual cycle phase, and suggests future directions for this line of research.