In the past month, two studies came to very different conclusions when examining if the human brain is capable of growing new neurons later in life. The first, published March 7 in Nature, found no evidence of neurogenesis in individuals older than 13 years old. But another study, released April 5 in Cell Stem Cell, claimed to find neuron generation in all the brains examined.

The question, for now, appears to still be open.

The latest study was conducted by a team from Columbia University, using brains donated after death from 26 people ranging in age from 14 to 79.

“[H]ealthy older subjects without cognitive impairment, neuropsychiatric disease or treatment display preserved neurogenesis,” wrote Maura Boldrini, MD, PhD, et al. “It is possible that ongoing hippocampal neurogenesis sustains human-specific cognitive function throughout life and that declines may be linked to compromised cognitive-emotional resilience.”

The researchers examined dentate gyrus, a part of the hippocampus that is thought to produce new neurons.

The results of the Nature study, however, appear to directly contradict Boldrini’s team. Lead author Shawn F. Sorrells—with the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at University of California San Francisco—and colleagues examined 59 brains and found no neurogenesis in brains past the age of 13.

“We conclude that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans,” Sorrells et al. wrote.