The Influence of Spatial Location and Object Shape on Learning and Re-Learning Spatial Tasks in Dopamine Transporter-Deficient Rats.

Background: The role of dopamine in brain functions has been well established, and dopamine imbalances can cause problems in working memory and spatial learning. The dopamine transporter (DAT) plays a significant role in dopamine regulation. Rats with a knockout of the dopamine transporter gene (DAT-KO), the model of attention deficit hyperactivity disorder (ADHD), are characterized by hyperdopaminergia and spatial memory impairments. Methods: Rats were trained to manipulate objects and recognize their spatial location and shape using RedBox apparatus. They needed to move a distant object to receive a food reward. After changing the shape and spatial location of objects, the ability to re-learning was evaluated. Results: We demonstrated that including objects to manipulate in the task conditions enables faster and stable learning of DAT-KO rats. The shape of the object did not influence the level of task performance, but changing the spatial location of the object led to the impairment of task performance in hyperactive rats. Conclusions: The data obtained highlight the role of hyperactivity and hyperdopaminergia in DAT-KO rats in spatial learning. We suggest that our findings may help in the further development of new training tasks for individuals with ADHD and spatial memory deficits.