The FIRSTS: Adult neurogenesis (1962)

New neurons in the granular layer of the hippocampus. Fig. 30 from Altman & Das (1965).
New neurons in the granular layer of the hippocampus. Fig. 30 from Altman & Das (1965).

I am starting a new category today: the Firsts. It will feature articles that showed something really interesting for the first time. Yes, all articles show something for the first time, that’s why they are published. But I have noticed either a lack of acknowledgment (“it is known that x”) or a disregard for the old papers (“doesn’t count if it’s before, say, 2001”), particularly among the new generation of scientists. So I will feature both the really big ones (e.g., first proof of adult neurogenesis) or the more obscure, but nonetheless, first in their field (e.g., first synthesis of morphine).

Today, first proof of adult neurogenesis. Altman (1962) wanted to see the kinetics of glial proliferation after brain injury. Glial cells are the other type of cells in the brain and they outnumber the neurons 10 to 1. Altman lesioned the rat lateral geniculate nucleus (a portion of the thalamus that deals primarily with vision) and then injected the rats with thymidine-H3, a dye that labels the newly formed cells. In addition to the expected glial proliferation, he also observed (by microscope and careful histology) that some neurons were also stained with the dye, which means that they were born after the injection. The new neurons were in many regions of the brain (so not only those associated with the lesioned area), including the cortical areas.

Altman followed up and three years later published the first comprehensive study of postnatal (not adult) neurogenesis in dendate gyrus of the hippocampus.

References:

  1. Altman, J. (30 March 1962). Are New Neurons Formed in the Brains of Adult Mammals?. Science, 135 (3509): 1127-1128. DOI: 10.1126/science.135.3509.1127. Article | PDF
  2. Altman, J, & Das, G. D. (June 1965). Autoradiographic and histological evidence of postnatal hippocampal neurogenesis in rats. The Journal of Comparative Neurology, 124 (3): 319 –335. DOI: 10.1002/cne.901240303. Article | PDF

by Neuronicus, 30 September 2015

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