Fig. 1

Depiction of the levels at which sex influences brain function. Sex modulates brain function and behavior through both acute effects (i.e., activational effects), as well as the programming of brain sensitivities during critical periods (i.e., organizational effects). These levels interact with one another in a dynamic fashion and include components within the central nervous system, in peripheral body systems, and external to the organism altogether (e.g., external environmental effects). Though not specifically explored in this paper, non-CNS physiologic factors including microbiome effects, immune response, and differences in peripheral organ/metabolic function are important when considering how sex influences the brain. Non-physiologic factors, such as social responses from others and meta-cognitive function, also play a significant role (from [38])