As c‐Jun N‐terminal kinase (JNK) plays an important role in the progression of insulin resistance and major pathologies of AD (Troy et al., 2001), we investigated the activation of JNK in the brain of APP/PS1 mice by assessing the level of its phosphorylation (p‐JNK) and the effects of intranasal insulin on JNK activation. Here, APP is linked to Alzheimer disease.