NE depletion further disrupted spatial memory function and activity in Ts65Dn mice. A) Performance in the WRAM is indicated by errors per trial across days (mean ± SEM, *p < 0.05 relative to NS Sal, ^p < 0.05 relative to Ts65Dn Sal). B) Analysis of errors across blocks (made up of three trials) demonstrate performance within each day of testing, and indicate that DSP-4 treatment alters “overnight remembering” on the first block of testing of days 2 and 3. C) Total activity was measured over a one-hour session (distance traveled, cm). D) Time spent in the center region, as a percentage of total time, showing that Ts65Dn mice spent less time in the center relative to NS mice (mean±SEM, *p < 0.05 relative to NS Sal; NS Sal n = 8; NS DSP-4 n = 8; Ts65Dn Sal n = 6; Ts65Dn DSP-4 n = 5).