Regression Analysis of the Relationship Between Neurogenesis and Maze Learning in Rats with Divergent Behavioral Phenotypes

The relationship between learning capacity and hippocampal neurogenesis is still poorly understood. Moreover, the effect of pathological behavior on this relationship is unknown. In this study, we investigated this problem in rats with different behavioral phenotypes. Wistar-Kyoto rats were used as a model for depression, and Spontaneous Hypertensive rats (SHRs) were used to model attention deficit hyperactivity disorder. Normotensive Wistar rats (NWR) served as a standard behavioral control. We trained rats in the Barnes maze and then assessed their cognitive flexibility. We estimated the density of doublecortin-expressing neural precursors in the dentate gyrus of the hippocampus dentate gyrus, and, finally, we applied regression analysis to study the relationship between learning indices and the DCX+ cell density. It was shown that SHRs exhibited poorer performance during the maze training, and WKY rats displayed the lowest learning efficiency. In NWRs and SHRs, learning did not correlate with ongoing neurogenesis, probably due to different biological substrates. In WKY rats, a strong inverse correlation was found between DCX+ cell density in the dentate gyrus and learning efficiency during training and reversed training sessions. These findings suggest that cognitive deficits in WKY are predominantly hippocampus-dependent, while cognitive problems in SHRs are primarily driven by dysfunction of other brain structures and impaired executive control.