Physiological, anatomical, and behavioral investigations on the bed nucleus of the stria terminalis

The anterior part of the bed nucleus of the stria terminalis (BNST-A) has emerged as a critical structure mediating fear and anxiety-like behavior. It is strategically situated to integrate information from limbic forebrain regions such as the amygdala, prefrontal cortex and hippocampus; and influence major fear and stress output effectors. Previous pharmacobehavioral studies have assumed that the BNST is a homogeneous structure despite the fact that anatomical studies contradict this assumption. The work presented in this thesis aimed to systematically examine the functional organization of BNST-A and its relation to anxiety-like behavior. In the first chapter, I examined the electroresponsive and morphological properties of BNST-A neurons. I showed that there are two dominant BNST-A cell types intermingled with at least other three less numerous cell types. In the second chapter, I investigated the intrinsic connections of BNST-A with the use of glutamate uncaging (GU). Overall, GU usually elicited inhibitory postsynaptic potentials and the incidence of intraregional connections was higher than interregional links. Lastly, I investigated the physiological properties of BNST-A neurons in a rat model of post-traumatic stress disorder. I show that neurons in BNST-A regions exhibit opposing alterations in synaptic responsiveness, supporting the idea that BNST-A is physiologically heterogeneous, with some regions exerting anxiolytic and others anxiogenic influences.Ph. D.Includes bibliographical referencesIncludes vitaby Olga E. Rodríguez-Sierr