The proposal aims to identify the neural substrates in the brain that are responsible for abnormal socio-emotional behavior. This understanding is vital for developing both diagnostic and therapeutic approaches to identify and treat the abnormal brain circuitry in neuropsychiatric conditions such as affective and anxiety disorders. The field of social behavior research still lacks appropriate animal models for social pathology that leads to inappropriate aggression, social anxiety/phobias, social withdrawal/detachment, impulsivity, or defensiveness. The study of the neurobiology of social behavior in non-rodent models is especially promising since the impairment in social interactions and emotional processing generates symptomatology that resembles psychopathology observed in human patients. Moreover these studies will permit an analysis of social interactions at a level not feasible in rodents. Therefore, this work promises to substantially advance our understanding of the neural substrates of human social interactions in the norm and pathology with a special relevance to anxiety and depression. The proposed research seeks to investigate the novel components of the amygdala-based network that regulates socioemotional responses in order to account for imbalances that can give rise to psychopathology in the absence of structural lesions. The effects of the DLSC manipulations on the vulnerability to behavioral abnormalities evoked by disinhibition within nuclei of the amygdala will be analyzed to determine the role of DLSC in mediating and/or modulating the influence of the amygdala circuitry. An understanding of the functional relationship between the amygdala-derived and colliculus- derived regulation of defensive and aggressive emotional tone is expected to reveal novel targets for both etiology and therapeutic intervention for affective and anxiety disorders.