514 



BRAIN MECHANISMS AND LEARNING 



These results add further evidence for the role of the temporal cortex of 

 monkeys in vision. That this cortical area is not necessary for simple visual 

 learning is also evident. The level of achievement on the learning-set 

 problem is positively correlated with the level of phylogenetic develop- 

 ment of the animal (Shell and Riopelle, 195X). The present finding indi- 

 cates the indispensable role of the temporal cortex for such a complex task. 

 Different neural mechanisms, at least at a gross level, must be sought in the 

 two types of visual learning. 



CA 5 



CA 6 



F1234 PI 23 y 4 



PROBLEM BLOCKS 



Fig. 3 

 Formation of leaming-set. Percentages of correct responses on the second 

 trial are plotted as a function of problem blocks. Monkeys Ca 3 and Ca 4 

 were trained after the third operation only. Monkeys Ca 5, Ca 6 were 

 trained after the first operation (interrupted line), tested after the second 

 operation (dash-dot line), and re-tested after the third operation 

 (straight line). P, preliminary sixty-seven problems; i to 4, successive 

 100 problem blocks; cross, percentages correct responses on the third 

 trials of the last one hundred problems. 



EEG CHANGES IN VISUAL AND TEMPORAL CORTICES DURING 

 LEARNING 



Most of the Studies on electroenccphalographic changes of the brain 

 during learning deal with the problem of functional localization (Gastaut, 

 1958; Rusinov and Rabinovich, 1958; Morrell, 1959; Galambos, 1959). 

 As with the ablation method, such studies are a necessary first step. Once 

 an electrographic change is localized to a neural structure, unless the 

 genesis of the potentials is understood the mechanism of learning remains 

 difficult of translation into neuronal terms. Furthermore, in order to 

 establish such a correlation, the electrographic changes should follow the 

 behavioural changes as expressed in learning curves. Except in a few cases, 

 such a correlation has not been convincingly reported (Yoshii, 1956; 



