Fig. 2

Animal allocation in the current study. Eighty-three rats were trained in 10–12 sessions (20 min per session per day). The 76 rats that took more than 15 treats at the last training session were used for 4 sets of experiments and 7 rats that took less than 15 treats were excluded. (1) Time course changes after SNL with the object on the short route were examined in one cohort (total 12 rats) including 6 normal and 6 SNL rats. (2) Effects of object placement and oral gabapentin in the shuttle maze test were examined in two cohorts of total 32 rats (16 rats/cohort). In each cohort, animals were randomly assigned to normal and SNL groups (8 rats in each group), and shuttle maze tests were performed starting from 2 weeks after SNL surgery (see “Methods” for detail). (3) Effects of intrathecal idazoxan in SNL animals treated with oral gabapentin in the shuttle maze test were examined in one cohort of total 16 rats. (4) Influences of sham surgery on preference index and gabapentin’s effect in the shuttle maze test were examined in one cohort (total 16 rats) including 8 normal and 8 sham rats