The stria terminalis (or terminal stria) is a structure in the brain consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus. Serving as a major output pathway of the amygdala, the stria terminalis runs from its centromedial division to the ventromedial nucleus of the hypothalamus. Anatomy The stria terminalis covers the superior thalamostriate vein, marking a line of separation between the thalamus and the caudate nucleus as seen upon gross dissection of the ventricles of the brain, viewed from the superior aspect. The stria terminalis extends from the region of the interventricular foramina to the temporal horn of the lateral ventricle, carrying fibers from the amygdala to the septal nuclei, hypothalamic, and thalamic areas of the brain. It also carries fibers projecting from these areas back to the amygdala. Bed nucleus of the stria terminalis (BNST) The activity of the bed nucleus of the stria terminalis correlates with anxiety in response to threat monitoring. It is thought to act as a relay site within the hypothalamic-pituitary-adrenal axis and regulate its activity in response to acute stress. However, the stress response is time related and the BNST does not activate for contextual fear. This means that a sudden scary situation that is under ten minutes long, does not activate the BNST. It is also thought to promote behavioral inhibition in response to unfamiliar individuals, by input from the orbitofrontal cortex. Bilateral disruption of this pathway has been shown to attenuate reinstatement of drug seeking behaviour in rodents. This nucleus is known to project inhibitory fibers to the lateral hypothalamus and participate in the control of feeding in rodents. Optogenetic activation of this inhibitory pathway rapidly produced voracious feeding behavior in well-fed mice and optogenetic inhibition of this pathway reduces food intake even in starved animals. Derangement of opioid signaling in the BNST appears to mediate chronic alcohol-induced changes in stress response. Sexual dimorphism The central subdivision of the bed nucleus of the stria terminalis (BSTc) is sexually dimorphic. On average, the BSTc is twice as large in men as in women and contains twice the number of somatostatin neurons. A sample of six post-mortem, long-term hormone replacement therapy (HRT) treated trans women (male-to-female) were found to have a female-typical number of cells in the BSTc, whereas a trans man (female-to-male) was found to have a male-typical number. The authors (Jiang-Ning Zhou, Frank