Newborn neurons in the adult hippocampus are critical for memory retrieval, reports a study published this week in Nature Neuroscience. The study found that silencing newly generated neurons four weeks after their “birth” impaired memory retrieval in adult mice.
Shaoyu Ge and colleagues determined when newborn neurons were born in the adult hippocampus and then specifically silenced neurons of different ages. They found that silencing four-week-old neurons, but not older or younger neurons, led to impaired memory retrieval in tasks known to depend on the hippocampus. Four-week old neurons are known to be more responsive to change than existing neurons, and these findings suggest their increased plasticity may render them essential for memory retrieval.
While it is well-known that newly born neurons are present in the hippocampus of adult animals, the function of these newborn neurons has remained somewhat controversial. These findings add support to the idea that the generation of new neurons in the adult hippocampus may be crucial to support normal learning and memory processes.