Fig. 4. Immunisation leads to an impaired spatial memory comparable to that observed in tPA-deficient mice. (A) In the Y-maze task, spatial memory was clearly impaired in tPA-deficient mice when compared with WT littermates as assessed by the time spent in the new arm compared with the two others. (B) A similar deficit was observed in NTD-NR1-immunised mice when compared with control or CFA-injected mice. (C) Plot of all the parameters used to quantify the performance in this task (time spent and number of entries in each arm). There is a positive correlation between the effect of tPA deletion and that of vaccination (R²=0.67, P<0.001).