The results obtained from this project are very important since, the dysregulation of the DA system is associated with several psychiatric and neurological diseases, such as Parkinson’s, Alzheimer’s, Huntington’s, schizophrenia and restless leg syndrome and with the pathophysiology of stress-related illnesses, such as depression. In addition, DA has a pivotal role in addiction. In this context, the zebrafish has in recent years gained popularity as a model for the study of central nervous system function, particularly in the study of psychiatric and neurological diseases, including those associated with DA systems. However, as mentioned above, even though several studies have linked the DA system to have the same function in fish as in mammals, there is a lack of functional studies that have concentrated on the normal function (i.e. in healthy functioning animals) of DA in fish. For example, even though several studies have mapped the location of different DA neuronal populations, these studies have not included functional analysis of DA neurons to reward and have therefore only speculated on which populations may be important reward centers in the zebrafish brain. Notably, a recent study pinpoints to forebrain DA populations being more important than midbrain populations in the processing of reward stimuli in fish and this is in agreement with our results. That is, we mapped activity of specific DA neuronal populations to reward and found that forebrain DA neurons of the Vd and Vv are important centers for reward processing. This is the first time that this has been achieved and importantly, it helps validate the use of fish models for the study of DA related illnesses, since it confirms that DA neuronal networks work in the same way in fish as it does in humans. These results will aid in the understanding of neural mechanisms and development of treatments for neurological diseases associated with DA function. With the execution of this project the fellow learned valuable skills in visual imaging techniques, optogenetics, microscopy, fish husbandry, RNA sequencing and laser capture microdissections, which was used in the study of functional neuroanatomy in fish, an area in which the fellow wishes to specialize in. In addition, this experience gave the fellow the possibility of running a project in an independent manner but with the possibility of having a senior colleague at hand when required. All these skills have helped the fellow mature in his professional academic career. Thanks to the skills and execution of the current project the fellow has been able to procure financing for the execution of another functional neuroanatomy project and is in the process of applying for financing of several other projects in which the skills learned during the FISHDOPA project will be utilized. Importantly, the innovation activities carried out during this project include the development of new behavioral assays that will benefit the scientific community.