Table 1.

Pearson correlations (r) between locomotion during inescapable novelty or following the first drug injection and measures of locomotion after injection (saline or drug).

	0.5 mg/kg AMPH		1.0 mg/kg AMPH		0.5 mg/kg METH		1.0 mg/kg METH
	S−	S+	S−	S+	S−	S+	S−	S+
Novelty
Conditioning	−0.275	−0.928**	0.363	0.323	0.192	−0.141	−0.112	0.026
Acute drug	0.542	−0.316	0.677	0.766*	−0.492	−0.077	−0.372	0.641
Drug challenge	−0.024	−0.489	0.717*	0.805*	−0.282	−0.339	0.415	0.551
Sensitization (diff.)	−0.613	−0.268	−0.052	0.016	0.371	−0.232	0.576	0.144
Sensitization (norm.)	−0.735*	−0.216	−0.319	−0.434	0.269	−0.227	0.276	0.003
Acute Drug
Conditioning	0.496	0.447	−0.047	0.293	0.281	0.481	0.227	−0.095
Drug challenge	0.447	0.125	0.683	0.823*	0.730*	−0.421	0.071	0.554
Sensitization (diff.)	−0.804*	−0.438	−0.518	−0.354	−0.564	−0.714*	−0.704*	−0.139
Sensitization (norm.)	−0.918*	−0.589	−0.753*	−0.831*	−0.774*	−0.778*	−0.919*	−0.405

Cumulative locomotion during the 30 min following the first exposure to the open-field arena (Day 1 of testing) was used to define each rat’s novelty response. Conditioning was defined as the difference between locomotion during the 30-min period after saline injections on the acute and challenge days (Days 1 and 10, respectively). Cumulative locomotion during the 60-min period after AMPH or METH injection was used for measures of drug-induced behavior (acute and drug challenge). For sensitization, two measures were used: the difference (diff.) in locomotion for the 60-min period after injection on challenge and acute treatment days, and a normalized (norm.) measure that controlled for individual differences in the acute response to AMPH or METH by dividing the difference score by the post-injection activity measured after the first injection.