Fig. 7

a Before the surgery on the continuous training days, the escape latency of three groups decreased day by day. There was no interaction between time and different intervention. Each day, the escape latency were no significant difference between three groups. b After the surgery, the escape latency and times of crossing platform in the S group were significantly different with these of the C group. The escape latency, duration of platform and times of crossing platform were similar in the C and SV groups. Although these parameters relating to study and memory were ameliorated by VNS, the difference was not significant