Sisti, Helene M.. Learning and neurogenesis: are new cells rescued from death with each new learning experience?. Retrieved from https://doi.org/doi:10.7282/T3XP7594
DescriptionNew cells in the adult hippocampus become apoptotic, e.g. begin programmed cell death, about one week after they are generated. If animals begin to learn a hippocampal-dependent task, at precisely the time when these cells would normally begin apoptosis, then the fate of these cells is altered. Instead of dying, the newly generated cells survive. These new cells differentiate into mature neurons and become fully integrated into the hippocampal network. Thus far, much of this work has focused on a single training experience. An important question has yet to be addressed: are new cells rescued from death with each new learning experience? In the present series of experiments, animals were trained with two phases of eyeblink conditioning. During the first phase, animals either learned the same task, a different one, or remained in their home cage. A single injection of BrdU was given after the first training experience had been completed, and one week before the start of the second training experience. Animals that were trained with a single phase of eyeblink conditioning retained more BrdU-labeled cells than those trained with two phases or no training at all. When animals were re-categorized based on learning during the second phase, instead of by training condition, there was a significant positive correlation between improvement and number of new neurons. Animals that demonstrated a larger degree of improvement retained more one week old neurons than animals that did not learn very well, regardless of previous experience. Overall, these data suggest that even during a second training experience, learning can rescue one week old neurons from death.