Chapter 18, Figure 5

(A) Neuron number per 1 mm2 column for 35 areas of the human cerebral cortex. These data were corrected for shrinkage due to the methods of tissue preparation used by Conel as well as for stereological error (see text in chapter 18 for details). One can see a common pattern of rises and falls in neuron number, with most cortical areas having a nadir value at 15 months. However, detailed analysis of these data identified 15 patterns of increases and decreases among the 35 cortical areas. (B) Same data as in panel (A) except that the values of each of the 35 cytoarchitectonic areas are normalized by their birth values. This normalized changes in neuron number per 1 mm2 column more clearly show the variability in the patterns of increases and decreases in neuron numbers across different cytoarchitectonic areas. The majority of areas still reach their nadir values at 15 months. Note also that all areas increase their numbers of neurons from 15 to 72 months.