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ARCHIVES OF XEUROLOGY AND PSYCHIATRY 



Table 1.— Average Time in Seconds Per Trial Consumed in Opening Each 



Problem-Box in Each Day's Practice of Training, Preliminary Retention 



Tests and Postoperative Retention Tests 



Tests for visual discrimination were made. There was no error in 100 

 trials. At all times following the operation the animal was oriented in the 

 cage and room and. with the exception of the motor disturbance, gave no 

 indication of anv deterioration. 



Fig. 1. — Extent of lesions in animal Xo. 1. 

 sketch and serial sections. 



Reconstructed from camera 



Extent of Lesions. — The areas destroyed are shown diagrammatically in 

 Figure 1 and in sections in Plate 1. 



Left Hemisphere: Mediad, the lesion began about 1 mm. behind the end of 

 the fissure of Rolando and extended forward to the level of the knee of the 

 corpus callosum. The cortex of the precentral gyrus was destroyed to within 

 2 mm. of the edge of the longitudinal fissure, but that of the median surface 

 was uninjured. Caudad, the lesion extended slightly onto the postcentral gyrus 

 but did not involve all of the cortex within the fissure of Rolando. Laterad, it 

 extended to the upper border of the operculum. The parts of the stimulable 

 area left intact were the paracentral gyrus, the cortex within the fissure of 

 Rolando and the lateral part of the face area included on the operculum. 



