Table 1. Details of the experimental protocol in all three conditions of the experiment. The first column under each condition presents the pulse frequency (N) of the brain stimulation reward for each rat (i.e., reinforcer magnitude). The remaining columns give the exact number (and percent) of reinforced and peak trials actually received by each rat totalled over the final five sessions for each of the three experimental conditions.

Rat	Condition 1: High reinforcer magnitude				Condition 2: Low reinforcer magnitude				Condition 3: High reinforcer magnitude
	N	Rf. Trials	Peak Trials	% Peak	N	Rf. Trials	Peak Trials	% Peak	N	Rf. Trials	Peak Trials	% Peak
V1	63	734	187	20.3	50	752	179	19.2	63	744	185	19.9
V2	100	623	300	32.5	63	649	289	30.8	100	656	268	29.0
V3	79	618	319	34.0	63	645	281	30.3	79	659	285	30.2
V4	100	624	310	33.2	63	655	293	30.9	100	641	282	30.6