Pasko questions adult brain neurogenesis

In this week’s SCIENCE, Rakic reviews a recent paper in PNAS (R. D. Bhardwaj et al., Proc. Natl. Acad. Sci. U.S.A. 103, 12564 (2006). [PNAS]) which uses 14C to study the question of adult neurogenesis. Bottom-line is negative.

Money quote
” The innovative study by Bhardwaj et al. demonstrates with advanced methodology–¹⁴C dating of cell births–that no new neurons are added to the human neocortex after birth. The authors take advantage of a transiently sharp increase in the level of the radioactive carbon isotope, ¹⁴C, in Earth’s atmosphere during the era of aboveground testing of nuclear weapons between the mid-1950s and the time of the nuclear Test Ban Treaty in 1963. In the years following these events, the level of ¹⁴C in the atmosphere declined to preexisting low background levels. The authors acquired cortical tissue from the autopsies of seven individuals born in Sweden between 1933 and 1973, and examined the level of ¹⁴C in individual cells by accelerator mass spectrometry. The presence of ¹⁴C in genomic DNA indicates that cells passed through their last cell division at a time when the atmospheric level of this isotope was high.”