AbstractsBiology & Animal Science

The Bed Nucleus of the Stria Terminalis (BNST) is a basal forebrain structure that is regarded as a part of the extended amygdala and therefore of the limbic system. It is supposed to play an important role in the upkeep of anxious and avoiding behaviour in the presence of sustained contextual threats. Furthermore it is involved in pathological processes linked to the affective components of substance withdrawal, and a role in anxiety disorders and phobias, as well as eating disorders, has been discussed. In regard of these functions the structural connections of the BNST to cortical and subcortical structures are of particular importance. They have already been elaborately examined in a multitude of animal studies. However, a closer examination in humans fails at the necessity of invasive manipulation of the living brain. The thesis at hand now examines the fiber connections of the BNST using a non-invasive technique, the so called probabilistic fiber tracking (PFT) of diffusion-weighted magnetic resonance imaging data. This method has been used to evaluate the data of 73 healthy adult participants and those results that occured in the majority of cases were analyzed. Three main pathways could be identified with high inter-individual consistency: (1) A posterior pathway to the amygdala, identified as the stria terminalis. (2) A ventral pathway to the amygdala which shows high overlap with descriptions of the ansa peduncularis. (3) An anterior pathway that courses through the nucleus accumbens and the head of the caudate nucleus and reaches the orbitofrontal pole via the prefrontal white matter. The anterior pathway has not yet been discribed in this extent in animal models and therefore is discussed in detail. Further attention is turned to the fact that the data at hand only shows inconsistent connections to the brainstem which have been discribed on a regular basis in animal studies.; Der Bed Nucleus der Stria Terminalis (BNST) ist ein Kerngebiet des basalen Vorderhirns, das funktionell der erweiterten Amygdala als Bestandteil des limbischen Systems zugeordnet wird und eine herausragende Rolle in der Aufrechterhaltung ängstlich-vermeidenden Verhaltens in Gegenwart andauernder, kontextueller Bedrohungen spielt. Zudem ist der BNST in einer Reihe pathologischer Vorgänge im Rahmen der affektiven Folgen des Substanzentzugs involviert und seine Beteiligung an Angststörungen und Phobien sowie an Essstörungen wird diskutiert. Im Rahmen dieser Funktionen sind die anatomisch-strukturellen Verbindungen des BNST zu kortikalen und subkortikalen Zentren von herausragender Bedeutung. Diese wurden bisher ausführlich in einer Vielzahl von Studien an Tieren untersucht. Bei Menschen scheiterte eine nähere Untersuchung bisher an der Notwendigkeit des invasiven Vorgehens am lebenden Gehirn. Die vorliegende Dissertation untersucht nun die Faserverbindungen des BNST des Menschen mithilfe eines nichtinvasiven Verfahrens, des sog. probabilistischen Fiber-Trackings (PFT) von diffusionsgewichteten magnetresonanztomographischen Daten. Das… Advisors/Committee Members: Ethofer, Thomas (Prof. Dr.) (advisor).