432 Exp Brain Res (2011) 214:427–435 Fig. 4 Mean total times, reaction times, and movement times for the random blocks (R1 and R2) and the Wxed-sequence blocks (L1-L4) per group for the Pattern Learning Task (PLT). Error bars reXect standard errors Fig. 5 Mean directional error rates across the random blocks (R1 and R2) and the Wxed-sequence blocks (L1-L4) for the Pattern Learning Task (PLT) The mean DE rate on the six blocks for both groups is presented in Fig. 5. The DEs between blocks L4 and R2 were signiWcantly diVerent in the two groups, with there being a signiWcant interaction between group and block (F(1,32) = 10.86, P = 0.002). Paired t tests (L4-R2) showed a signiWcant increase in the control group (t(13) = ¡6.93, P < 0.001), but not in the KorsakoV group (t(19) = ¡0.71, P = 0.49). The correlations between RT and DE rate were large and signiWcant. In the control group, the correlation changed from r = ¡0.57 (P = 0.034) in block L4 to r = ¡0.96 (P < 0.001) in block R2. In the KorsakoV group, the corre- 123 lation remained the same (r = ¡0.75, P < 0.001 in block L4, and r = ¡0.75, P < 0.001 in block R2). Explicit knowledge Eleven participants (Wve KorsakoV patients [25%] and six controls [43%]) remarked that they felt the stimuli were not administered totally at random in the SSRT, and 13 partici- pants (seven KorsakoV patients [35%] and six controls [43%]) made the same comment regarding the PLT, imply- ing they had some explicit knowledge of the sequences. Because of the experimental design, participants were asked about this only at the end of the study. However, in the control group the results of participants with and with- out knowledge were similar on the SRTT (RT: F(1,12) = 0.81, P = 0.39; error rate: F(1,12) = 1.02, P = 0.34) and the PLT (RT: F(1,12) = 1.18, P = 0.30; DE: F(1,12) = 0.43, P = 0.53), and this was also true for the KorsakoV group: SSRT (RT: F(1,18) = 0.03, P = 0.87; DE: F(1,18) < 0.01, P > 1.00) and PLT (RT: F(1,18) = 0.001, P = 0.97; DE: F(1,18) = 1.41, P = 0.25). Discussion In this study, we investigated the implicit learning abilities of patients with amnesia compared with healthy controls. As expected, implicit learning of the motor sequences of the SRTT was similar in the patients with KorsakoV’s syn- drome and in the matched controls, as reXected by the RTs, and learning of the PLT was worse in the patients with KorsakoV’s syndrome than in the controls, as reXected by the diVerence in accuracy.