TY - JOUR TI - Physiology of the extended amygdala DO - https://doi.org/doi:10.7282/T34T6NFK PY - 2017 AB - Based on anatomical similarities, it has been argued that the amygdala, bed nucleus of the stria terminalis (BNST) and adjacent components of the basal forebrain constitute a single system, termed the extended amygdala, which plays a critical role in emotions. In the first part of this thesis, I studied the role of BNST in the genesis of conditioned fear by recording neurons in the anterolateral (AL) and anteromedial (AM) regions of BNST in rats. During habituation, few neurons were responsive to the conditioned stimulus (CS). After fear conditioning, 20% of BNST-AL neurons developed inhibitory responses to the CS. In BNST-AM, 26% of neurons developed positive CS responses. Activity of BNST-AM and AL neurons during contextual fear paralleled their CS responsiveness, suggesting they exert opposite influences on fear output networks. During these experiments, I observed a hitherto unreported rhythm at ~140 Hz (termed high frequency oscillations or HFOs) in the local field potential of BNST. The second part of my thesis characterized HFOs, revealing a systematic dependence on behavioral state, a pronounced relationship to extended amygdala unit activity, coherence between distant sites, and coupling with lower frequency gamma activity. However, the origin, and nature of the HFO-gamma relationship remained unclear. This was explored in the last part of my thesis. I found that HFOs and gamma are related through a generic phenomenon, manifest throughout the brain, whereby novel rhythms arise when signals combine in the presence of a non-linearity. KW - Neuroscience KW - Amygdaloid body--Physiology LA - eng ER -