PLE and working memory
Pearson’s correlation was used to assess how changes in PLE scores (d-amphetamine–placebo) relate to WM change scores (d-amphetamine–placebo). There was a significant negative correlation between d-amphetamine induced changes in PLE and changes in WM (maximum obtained) at the 8 s delay (r = -0.47, p = 0.03, n = 20), but not at 0 s (r = 0.28, p = 0.22, n = 20), 4 s (r = 0.09, p = 0.69, n = 20), or 6 s (r = 0.10, p = 0.67, n = 20).To assess which span tasks influenced the association between the WM change and PLE change, we did separate analysis for each SWM and VWM at each delay condition. There was a significant negative correlation between changes in PLE and changes in SWM (r = -0.58, p = 0.006, n = 20), but not between changes in PLE and changes in VWM (r = -0.01, p = 0.96, n = 20) at the 8 s delay, indicating the correlation between WM and PLE was mainly influenced by SWM.