Exercise reverses learning deficits induced by hippocampal injury by promoting neurogenesis

Hippocampal atrophy and cognitive decline are common sequelae of neurodegenerative disorders and stroke. To test whether exercise-induced neurogenesis can ameliorate cognitive decline, female C57BL/6 mice received a unilateral hippocampal injury via intrahippocampal endothelin-1 (ET-1) injection and then had 21 days of voluntary wheel running. Severe spatial learning deficits in the active place-avoidance (APA) task following injury were almost completely restored in animals that ran, whereas non-runners showed no improvement. Running increased neurogenesis in both the injured and contralateral hippocampi. Bilateral ablation of newborn doublecortin (DCX)-positive neurons abrogated the cognitive improvement, while unilateral ablation did not prevent recovery, indicating that elevated neurogenesis in either the damaged or intact hippocampus is sufficient to reverse hippocampal injury-induced learning deficits.

Lavinia N. Codd, Daniel G. Blackmore, Jana Vukovic, Perry F. Bartlett