Sex differences in neuromodulatory subcortical systems and their implications for Alzheimer's disease

Neuromodulatory subcortical systems (NSSs) are uniquely susceptible to dementia-related pathology, leading to frequent molecular and behavioral impairments associated with altered function of these nuclei. Some of these systems display clear sex-specific cytoarchitecture and signaling leading to distinct physiology and behavioral outputs in males and females, while other regions display nominal sex differences. However, the relevance of sex differences in modulating dysfunction of NSSs in Alzheimer's disease (AD) and related dementias is not well understood. This review is a joint effort by the Neuromodulatory Subcortical Systems and Sex and Gender Differences in Alzheimer's Disease Professional Interest Areas of the Alzheimer's Association. We review sex differences in NSSs, both in non-disease states and in AD models and patients. We highlight the possible role of NSSs in driving sex-specific AD susceptibility and potential footholds for sex-based interventions targeting these systems. We conclude by outlining immediate and long-term actions to address the intersection of NSSs, sex, and AD.