Three-Dimensional Dissection of the Bed Nucleus of the Stria Terminalis and Its White Matter Connections: A Surgical and Neuropsychiatric Perspective.

Aim: The bed nucleus of the stria terminalis (BST), situated deep within the basal forebrain, serves as a key relay in circuits regulating emotion, stress, and autonomic responses. Despite its clinical relevance, particularly in anxiety-related disorders, its detailed white matter connectivity remains underexplored. This study aims to provide an in-depth anatomical description of the BST and its structural affiliations, with an emphasis on its surgical and neuromodulatory relevance.

Material And Methods: We conducted stepwise fiber dissections on 14 formalin-fixed human brains prepared using the Klingler method. Under high magnification, dissections were performed lateral to medial and medial to lateral directions, enabling detailed visualization of the BST's relationship with adjacent fiber tracts and nuclei such as the anterior commissure, fornix, stria terminalis, nucleus accumbens, and septal area.

Results: The BST was consistently located anterosuperior to the anterior commissure and medially bordered by the septal nuclei, forming a compact yet integrative structure. Dense projections were identified between the BST and limbic-hypothalamic targets via the stria terminalis, fornical fibers, and the diagonal band of Broca. These connections emphasize the BST's pivotal position in coordinating limbic output with neurovegetative centers.

Conclusion: This study refines the topographic and connectional map of the BST, offering structural insight into its role as a limbic hub. Such clarity may assist in tailoring neuromodulatory interventions-such as deep brain stimulation-by improving anatomical precision in disorders involving fear, compulsion, and affect regulation.