In order to assess the effects of PEG-IGF-I treatment on changes in synaptogeneis, we investigated the presynaptic marker synaptophysin using Western blot analysis on peri-infarct tissue isolated from around the stroke site (ipsilateral: Fig. 6A) and corresponding brain region on the non-stroked side (contralateral: Fig. 6B) of young sham and stroke mice. Here, SYP is linked to Stroke.