Thesis: Emerging evidence describe neurological effects on adult exposure to radiation at dose rates much lower than previously thought in humans including elevated risk of Parkinson’s disease and cerebrovascular defects. The alteration of central nervous system integrity caused by chronic exposure to low to moderate dose rates of IR could thus affect major processes such as reproduction and behavior. To evaluate the impact of IR on adult brain zebrafish, we exposed the whole organisms to three dose rates (0,05 mGy.h-1; 0,5 mGy.h-1 et 5 mGy.h-1) for 36 days. Transcriptomic studies associated with RNA in situ hybridization analysis showed the increased expression of genes with function in neurotransmission or stress and identified potential biomarkers (oxytocin, arginin-vasopressin, cone rod homeobox) specific to ionizing radiation exposure compared to physical injury through stabwound. In our experimental conditions, we observed the induction of neurogenesis contrarily to the impact of acute and high doses of IR where neurogenesis is reduced. While after stabwound injury, reactive neurogenesis is dependent on inflammatory processes, here neuro-inflammation was not initiated thus proposing a compensative system through potential anti-oxidative action of oxytocin and the anti-inflammatory role of cortisol. These modifications on the molecular scale impacted the behavioral response specifically on female zebrafish with increased stress and reduction of sociability. Altogether, these findings highlight the intricate interaction between neurohormones, neurotransmission and neurogenesis process to balance the disturbed brain homeostasis caused by our experimental conditions