STUDIES OF CEREBRAL FUNCTION. IX 



35 



portions with error scores is less (0.49 and 0.35), but is as 

 great as is to be expected, considering the reduction in range 

 of lesion when computed on this basis alone. There is a still 

 smaller correlation between the extent of symmetrical and 

 asymmetrical lesion. This may be responsible for the ap- 

 parent correlation between the latter and error scores. We 

 have attempted to partial out its influence, with the results 

 shown in the last column of the table. Not much weight can 

 be ascribed to such statistical analyses, however, since the 

 relationships are not rectilinear and the data have not normal 

 distribution. The partial correlations (asymmetrical lesion 

 with errors, with the influence of symmetrical lesions held 

 constant) seem still significantly large and suggest that the 

 asymmetrical portions of the lesions contribute to the 

 deterioration as do the symmetrical portions. 



TABLE 17 



Comparison of the effects of lesions common to the two hemispheres and of the 



asymmetrical portions of the lesions. The correlations are between extent 



of lesion and scores for errors less first trial in learning maze V 





The relative influence of lesions within different 

 cyto architectural fields 



Lashley ('29) attempted to estimate the effectiveness of 

 injuries within each of the chief functional fields by grouping 

 his cases according to the field most seriously involved and 

 computing constants for each group. The small number of 

 animals which he had available made it necessary to include 

 ambiguous cases, and inspection of his figures shows that 

 there was an extensive overlap between the groups. This 

 considerably reduces the validity of the evidence presented 

 for equal effects of equal lesions in different areas. 



We have sought a more conclusive test of the matter by 

 selecting nearly unequivocal cases from our data. Since there 



