Detection of salient stimuli or environmental changes is a key mechanism that facilitates associative learning by allocating attentional resources toward biologically significant. The detection of salience is highly dynamic and influenced by a wide range of factors, including past experiences, arousal, emotions, stressful events, and internal homeostatic needs or environmental changes. However, in some cases, irrelevant events acquire saliency, whereas biologically significant events do not. Such misallocation of the salience of external and internal signals is often associated with altered inhibition of automatic responses and impaired goal-directed behaviors which constitute core symptoms shared by several neurodevelopmental and psychiatric disorders. Widely distributed circuits in the animal and human brain are activated by salient stimuli and increasing evidence indicates that dorsal subicular circuits are essential for the detection and processing of salient contextual stimuli. These regions comprising the prosubiculum receive projections from the locus coeruleus and the ventral tegmental area, two monoaminergic nuclei also highly reactive to stimuli perceived as salient. Although recent findings indicate that hippocampal monoamine transmission might be critical for the detection of contextual salient stimuli, dorsal subicular circuits, and the underlying cellular mechanisms through which monoamine signaling modulates salience detection remain to be elucidated. By combining advanced circuit-mapping, intersectional genetics, ex and in vivo electrophysiological recording and behavior, SubDOPA aims to parse the role of the dorsal Prosubiculum (PSd) monoamine signaling not only in the detection of environmental changes but more generally in the detection and processing of salient stimuli and to understand how this may elicit attentional-behavioral switches allowing animals to select the most appropriate behavioral reactions toward biologically significant events. More specifically we will characterize the connectivity and function of PSd neurons responding to monoamines. We will monitor the dynamic of monoaminergic neuronal activity and release during environmental changes or salient stimuli presentation. We will investigate the impact of the detection of biologically salient events on the PSd neuronal network. The completion of SubDOPA will provide new insights into the neural circuits and cellular mechanisms controlled by monoamines involved in salience detection and will contribute to a better understanding of the emergence of deficits associated with aberrant salience which are core symptoms shared by several neurodevelopmental and psychiatric disorders.