Extended Amygdala

Determining the circuitry operant in the brain responsible for development of fear and anxiety is key to developing suitable treatments for the wide range of human anxiety disorders. The extended amygdala is a macrostructure in the forebrain that includes three key players in fear and anxiety-like behaviors: the basolateral nucleus of the amygdala(BLA), central nucleus of the amygdala (CeA), and bed nucleus of the stria terminalis (BNST). The BLA sends excitatory projections to both CeA and BNST, which in turn project to brainstem structures involved in the expression of fearful behaviors.The BNST is an important relay for multiple cortical and subcortical regions and sends diverse projections to many brain areas that are involved in fear/anxiety related
While CeA has been shown to be involved in the expression of both cued and contextual fear the BNST has been shown to be involved in the expression of contextual fear only. The basis for this difference has been attributed to regional differences in the activity of BNST-AL and -AM in relation to learned fear, raising the possibility that they exert opposite influences on fear output networks. The molecular mechanism underlying the differential activity in the subdivisions of BNST is unclear.The present study was undertaken to look at the molecular mechanism which control the differential activity of these sub-regions of BNST, during fear learning and its extinction. In the present study we worked towards the hypothesis that the differential activation of the neuronal subpopulations in the BNST and Amygdala is due to different expression patterns of memory related genes such as CREB in the neurons in these sub-regions and that this differential expression may be under the control of epigenetics especially Histone