BNST

The bed nucleus of the stria terminalis (BNST) is a collection of nuclei in the forebrain that forms part of the extended amygdala. Located adjacent to the stria terminalis and the anterior commissure, it lies dorsal and medial to the nucleus accumbens and rostral to the hypothalamus. The BNST is anatomically heterogeneous, with several subnuclei distinguished by cytoarchitecture, neurochemistry and connectivity.

Functionally, the BNST is implicated in the regulation of stress, anxiety and sustained threat responses. It is thought to mediate prolonged, diffuse emotional states rather than brief, cue-specific fear responses typically attributed to the central amygdala. The BNST influences autonomic, endocrine and behavioral components of stress via projections to the hypothalamus and brainstem, and through modulation of the hypothalamic–pituitary–adrenal (HPA) axis.

The BNST receives input from limbic regions including the amygdala, hippocampus and prefrontal cortex, and contains diverse neurotransmitter and neuropeptide systems such as GABA, glutamate, corticotropin-releasing factor (CRF), norepinephrine and oxytocin. These chemical signatures underlie its roles in anxiety, social behavior, sexual behavior and addiction-related processes.

Much of current knowledge derives from rodent studies; human imaging and postmortem work suggest conserved roles but also species differences in size and organization. Dysregulation of BNST circuits has been associated with anxiety disorders, post-traumatic stress disorder and substance use disorders, making it a target of interest for basic research and potential therapeutic intervention.