FETAL X-RAY EFFECTS: CEREBRAL CORTEX 



29 



lines indicate the maa;nitude of the standard errors of the mean for the con- 

 trols. Standard errors for the irradiated s^roups were not plotted in the 

 interest of clarity in the figures. 



Results 



Neuron packing density in all groups i Fig. 1 ) was seen to decrease very 

 rapidly between the 1- and 5-day stages, with a less notable decrease between 

 the 5th and 10th days, and approached normal adult levels on the 20th day. 

 The values for all irradiated groups and controls were in close agreement 

 and showed no significant differences at anv asje level. 



10.0 



9.0 



2.0 



1.0 



I- CONTROL 

 ^ - lOOr 

 = 200r 

 o = 300r 



5 10 



AGE (DAYS) 

 Fig. 1. Early postnatal changes in neuron packing density. 



20 



