Because alterations in locomotor activity during the place preference testing trials could possibly affect the expression of place preference [23], correlations between the place preference scores and the locomotor activities during the tests were determined. For both GluA1−/− and GluA1+/+ mice, Pearson correlation coefficients were calculated for each conditioning dose in two ways: first, separately for the groups tested in Sal-state and Mor10-state, and second, by pooling both state groups. In both cases the highest correlation score found was 0.43 (p>0.05), and thus in neither case were the correlations significant between the preference scores and locomotor activities (p>0.05, data not shown).
