The occurrence of adverse childhood experiences (such as abuse, neglect and bonding unsafe) has been related to the change in emotionality, may be understood as integral to the multifactorial etiology of psychological disorders. The impact of early experiences on adult behavior finds room to understand the characteristics of the development of the CNS (Central Nervous System) and the concept of neuroplasticity, neural capacity to mold according to environmental influences. Consistently, papers and research works show correlation between stress and early development of psychopathology. This work aims to understand the influence of childhood experiences in emotional behavior, and is justified in finding that this understanding can help to better comprehend mental illness and develop strategies for assessment and treatment more suitable and effective. To this end, held out an extensive literature review on the subject construction and evaluation of an animal model that could mimic the effects of early experiences on emotional behavior. The literature provides consistent data on these biobehavioral effects, often with the assistance, for this, of animal models in affective neuroscience. The experimental research was aimed specifically to assess whether different environmental conditions during the lactation of animals are able to change their emotional response in the EPM (Elevated Plus Maze), a behavioral assessment paradigm of emotionality. The procedures of handling and maternal separation in the first three postnatal weeks were applied and were evaluated in the EPM a total of 154 animals. Our findings with the procedure of handling were consistent between the different groups, but the effect seems to not be extend to adult animals. On the other hand, the maternal separation procedure used was not able to alter the emotional behavior, as found in the literature, where can be found contradictory results. Limitations of this work were the large number of variables and the small number of subjects per experimental group. More detailed studies and using behavioral paradigms that differ from those can be valuable for further discussion about the data. The findings of this study demonstrate the complexity of human emotionality, which could not be fully modeled. Future perspectives are presented on the investigation of the etiology of mental disorders taking into account not only environmental, but also those related to genetics and the interaction between them, attended by the procedure of cross-fostering. The clinical relevance of the research of childhood experiences is the knowledge about how they affect emotionality, leading to the development of mental illnesses. There seems to be consensus among studies regarding the deregulation of the HPA axis being repeatedly documented as a consequence of the initial experiences aversive psychobiological, having been proposed as a potential mediator of neurobiological long-term effects of negative emotional experiences.