Retrospective birth dating of cells in humans dating latin woman
While it might appear that these findings rule out the possibility of adult neurogenesis, at least in the occipital cortex of humans, there are some important points to consider.The first is whether or not this method is sufficiently sensitive to detect adult neurogenesis in any brain region.This would preclude the ability to detect an accumulation of adult neurogenesis over a very long period of time with a method that cannot examine individual cells.In summary, the paper by Spalding and colleagues (29) presents a creative and novel approach to investigating the age of neurons in the brains of humans born around the time of nuclear bomb testing.Since carbon dating does not allow for the birthdating of individual cells, a relatively large proportion of adult-born neurons would be necessary to detect an average age difference.The authors suggest that detectability limits are about 1 percent for their method (29), so one out of 100 neurons must be produced in adulthood to find adult neurogenesis in a given region.
Extensive testing of nuclear weapons resulted in a dramatic global increase in the levels of the isotope C in the atmosphere, followed by an exponential decrease after the test ban treaty in 1963.
Retrospective birth dating is a generally applicable strategy that can be used to measure cell turnover in man under physiological and pathological conditions.
About 40 years ago, Joseph Altman and his colleagues used the 3H-thymidine autoradiographic method to birthdate cells in the brains of adult rats and cats, and reported evidence for neurogenesis in the olfactory bulb, hippocampus, and neocortex (1-5).
In 1998, Eriksson and colleagues reported evidence for adult neurogenesis in the hippocampus of adult human cancer victims, using Brd U labeling (11).
Spalding and colleagues (29) did not examine the hippocampus in the present study, so this issue will require further experimentation.