664 



BILLEY LEVINSON 



30 



20 



10 



JCPP, 1959 



Present study, N=92 



225 275 

 39 33 



• = JCPP, 1959 

 0= Present study 

 X= Radiation + AET 



800 



600 



400 - 



Time (sec.) 



.H 



Radiation dose in r s 

 Fig. 1. Maze scores as a function of radiation dose. 



225 275 



The relationship between age at irradiation and performance deficit is 

 indicated in Fig. 2. Radiation in the first 6 days produced significant deficits 

 in adult learning. However, age at radiation was not an ordered variable, 

 since radiation interferes with developing cells which differ with neonatal 

 age. 



Figure 2 suggests there may be significant differences due to radiation at 

 2, 4, and 6 days, but these differences are not consistent with those of the 

 previous study. Also, in the earlier work (Levinson and Zeigler, 1959) the 

 greatest adult learning decrement appeared at day 4; while, in the present 

 data, the least effect occurred at this age. It is possible that these discrepan- 

 cies between the two studies are attributable to differences in the species and 

 radiation levels used, but further research is necessary to clarify the point. 



Groups receiving AET and those without chemoprotection differed signifi- 

 cantly for all three perfoiTnance measures. In fact (Fig. 2), the performance 

 of the AET groups in every instance approximated that of the nonirradiated 

 group, the most striking difference between protected and unprotected 

 groups appearing at the highest radiation level. There were no significant 

 differences between the 275 r AET and the nonirradiated groups in trial. 



