R. W. DOTY AND C. GIURGEA 



143 



MONKEY # 

 12 JULY 59 



r CLICKS T 



14 JULY 59 



, T „ T 



MOTOR CORTEX 

 0.4nnA 



15 JULY 59 



CLICKS TONE 



Fig. 5 

 Records of lever pressing for grape juice. The animal is rewarded for each 

 press and this is recorded by an upward excursion of the trace. On July 12th 

 for the fivc-minute period labelled 'clicks' between the arrows each lever- 

 press turned on a clicking sound for 3 seconds in addition to operating the 

 solenoid dispensing the juice. No tests were made on July 13th. On July 14th 

 coupling a cortical US with each Icvcr-press produced no disturbance in pressing 

 behaviour beyond that attributable to the violence of the UR. On July 15th the 

 same clicking sound used on July 12th now no longer disturbs pressing 

 behaviour, but introduction of a 2000 cycle tone with each press brought this 

 behaviour to a halt. Started again pressing without the tone by administration 

 of several 'free' millilitres of juice, the monkey continues to press with only a 

 minor slowing of rate when the tone is presented during a second period. 



