<正>Objective:To study the characteristics of latency of somatosensory evoked potential （SEP） and motor evoked potential （MEP） and the expression of nestin in subventricular zones （SVZ） after per- sistent focal cerebral ischemia in rats.Methods:The model of cerebral ischemia in rats was made by mid- dle cerebral artery occlusion （MCAO）.All animals of ischemia were sacrificed after 12h

1d

3d

7d

and 14d to observe the changes of latency of SEP and MEP and to detect the expression of nestin

with an immunohistochemieal approach.Results:The latencies of P1 （positive wave 1）

N1 （negative wave 1）and P2 （positive wave 2） in SEP were significantly prolonged after MCAO.The latencies of N1 and N2 waves in MEP were postponed gradually and no statistical difference of latency of N1 wave was found in rats at 7 d and 14d after MCAO.The expression of nestin increased at 12h

and showed a significant augmentation at 3d and peaked at 7d

then declined slightly at 14d after MCAO.Conclusion:The cerebral ischemia prolonged the latency of EP waves and the expression of nestin was up-regulated and reached the peak at 7 d

showing the ischemia induced the proliferation of nervous stem cells.The SEP and MEP may evaluate the proliferation in SVZ after brain isehemia.