STUDIES OF CEREBRAL FUNCTION IN LEARNING 



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was then placed in the left-hand feeding compartment in contact with the food, 

 and began to eat immediately. By the process of removing him a few inches 

 farther from the food at each trial, he was trained to find his way through the 

 training box from the starting compartment to the food. He was then given 

 regular training in visual discrimination for seven days. In this time he 

 showed no evidence of visual discrimination, but formed a position habit 

 toward the left alley, which was fixed in a normal learning curve, with errors 

 (turns to the right) as follow, in successive tens of trials : — 

 4:2:1:2:1:0:0. 



Fig. 5. — Extent of lesions in No. 17. In this and the following diagrams a uniform 

 arrangement has been adopted. Above, the lesions to the cortex are shown in lateral and 

 dorsal aspects. Below, at the left, is a diagram of the horizontal extent of the lesions to the 

 caudate nuclei, in this case embracing the entire extent of both nuclei. At the right is a 

 camera outline of a frontal section at the level of the anterior commissure, showing the 

 depth of the lesion. In these outlines degenerated areas are stippled and scar tissue, which 

 does not appear in this one, is shown in solid black. The outlines of the frontal sections are 

 reversed, the right side appearing on the left. The diagrams are correctly orientated. 



Ten days after operation he developed a marked spasticity and died on the 

 eleventh day. Autopsy showed the wound infected, with extensive abscesses in 

 both hemispheres, extending into the lateral ventricles. 



Extent of lesions (fig. 5). — Eight hemisphere : The entire cortex of the 

 dorsal surface of the hemisphere, from the frontal pole to the level of the 



