【Objective】 To study the optical intrinsic signal(OIS) imaging of peri-infarct depolarizations (PID) in mice and to investigate the influence of knockout of Kir6.1 on PID.【Methods】Kir6.1 knockout mice and wild type littermates were subjected to MCAO by standard intraluminal filament method. The main characteristics of PID were studied by 4-wavelength OIS imaging technique. 【Results】 PID were identified as consistent

red and blue interaction waves in cortical reflectance that slowly propagated peripherally from the origin site. There were 4 patterns of PID propagation including rostro-caudal

latero-medial

caudo-rostral

and contralateral pattern. Kir6.1 knockout mice had a mean of 25.5 ± 6.5 PID which was much higher than a mean of 15.5 ± 4.8 in wild type mice (P 0.05). Kir6.1 knockout mice showed an increased mean infarction volume (38.2 ± 7.5%) compared with wild type mice (27.8 ± 6.6%). 【Conclusion】 Using 4-wavelength OIS system

we are able to get high temporal-spatial resolution color images which are useful for analyzing temporal-spatial characteristics of PID in detail. Knockout of Kir6.1 facilitates induction of PID in focal cerebral ischemia

perhaps owing to decreasing spatial potassium buffering ability of astrocytes in kir6.1 knockout mice. Furthermore

more PID may contribute to the increased infarction volume in kir6.1 knockout mice.