Neural Mechanisms of Decision Making 



269 



al. (22, 23), who reported response to central stimulation after con- 

 ditioning to a peripheral stimulus. We came to the conclusion that 

 this difference might be due to the fact that our animals had been 

 highly overtrained to differential response, with punishment for 

 error. Subsequent pilot work by Karl Corley in our laboratories has 

 confirmed that central stimulation will elicit responses previously 

 established to peripheral stimuli when erroneous performance has 

 not been punished. Since our central stimuli had never been coupled 

 with primary reinforcement, we attempted to train these animals 

 to differentiate between the pulse trains which had been used in 

 the previous work. Frequency significance for each animal remained 

 the same as for the peripheral flicker. Thus, one can consider this 

 to be an attempt to transfer the differential response from inter- 

 mittent photic stimulation to intermittent central stimulation. 



Figure 14 shows the learning" curve for Cat 4. Differential training 

 was instituted at the arrow after reliable performance of the avoid- 

 ance response had been established to four per second bursts 

 delivered to the electrodes on left and right visual cortex. Trials 



CAT 4 

 CENTRAL CONDITIONING USING BILATERAL STIMULATION 

 OF VISUAL CORTEX 



25 I 58 I 

 50 83 



8 9 10 

 SESSIONS 



CUMULATIVE TRIALS 



-T— 

 101 



I 121 I 171 I 

 112 146 183 



16 



— I— 

 30 



— r- 



40 



— r- 

 63 



8 13 17 25 



Fig. 14. Learning curve for avoidance response to direct central stimulation in 

 cat previously differentially trained to flicker conditioned stimulus. At arrow 

 central diff"erentiation training began (4 per second — S , 10 per second — S'^). 



