LIVERMORE, Calif. -- Using data derived from nuclear weapons testing of the 1950s and '60s, Lawrence Livermore scientists have found that a small portion of the human brain involved in memory makes new neurons well into adulthood.
The research may have profound impacts on human behavior and mental health. The study supports the importance of investigating the therapeutic potential of applying adult neurogenesis to the treatment of age-related cognitive disorders.
Neurogenesis is the process by which neurons are generated from neural stem and progenitor cells, and, until now, were believed to be most active during pre-natal development.
LLNL's Bruce Buchholz, colleagues from the Karolinska Institute in Sweden and international collaborators found that hippocampal neurogenesis occurs at significant levels through adulthood and into old age. (Humans and other mammals have two hippocampi, one in each side of the brain.)
The hippocampal portion of the brain is thought to affect memory. Research has shown that people with a damaged hippocampus can have a variety of memory issues including long-term memory loss, loss of conversion of short-term to long-term memory or no spatial navigation.
The team used carbon 14 dating techniques, typically used in archaeology, to date cells in the hippocampus. The technique is based on the spike in global levels of carbon-14 that resulted from extensive above-ground nuclear weapons testing during the Cold War. Since the test ban, there has been a steady decline in atmospheric carbon 14.
Because plants absorb carbon 14 via CO2 during photosynthesis, animals that eat them also take in radioactive carbon; therefore, the carbon 14 level in the human body reflects that of the atmosphere. When a cell divides, newly synthesized DNA integrates a trace amount of carbon 14 that is proportional to the environmental level at the time of mitosis; so, the radioactivity of a cell nucleus can be
|Contact: Anne Stark|
DOE/Lawrence Livermore National Laboratory