KAC) LIANC; CHOW 



517 



regular and appeared in all records. When the training started, photic 

 driving was prominent in the visual area. This driving habituated rapidly, 

 usually within the first thirty trials. It very rarely appeared in the temporal 

 tracings. 



By inspection, the visual area EEG of each trial throughout the learning 



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Fig. 5 

 EEG records of four negative trials taken from the second day of training. Monkey C2 made 

 53 per cent correct responses on vertical and horizontal striation discriminations on that day, 

 but responded incorrectly to these four trials. Trials 6 and 19 show the decreased amplitude of 

 temporal cortical EEG, and trials 19 and 5 show photic driving in the visual area tracings. 

 The break in the upper tracings of light flashes indicates the presentation of the stimulus. The 

 arriiw shows the animal reaching the stimulus. LT, left temporal; LV, left visual; calibration, 

 SO uv. and I sectind. 



process was judged as showing or not showing photic driving. For the 

 temporal lobe, the disappearance of the periodical bursts accompanied by 

 a decreased amphtude of the entire record was seen after exposure of the 

 visual stimuli. No other EEG alterations were recognized. These changes, 

 however, were not consistent, being present in one trial and absent in the 

 next. Also, these changes occurred mostly during negative trials. Fig. 5 



