highly significantp < 0.001
On more difficult trials with delays of 21–30 s and five or six images, the overall mean increase of 25% in performance in the normal + CX717 condition relative to normal vehicle condition was also highly significant (mean normal vehicle, 46.7% ± 4.8% versus mean normal + CX717, 71.7% ± 2.4%; F [1,1759] = 26.46, p < 0.001).