To investigate the impact of abnormal α‐synuclein accumulation on the cholinergic system, we evaluated ACh levels in the frontal cortex and hippocampus, where marked reduction in ChAT activity has been observed in patients with DLB and PDD.4, 5, 7 ACh levels in the frontal cortex, but not in the hippocampus, of the CaMKIIα‐tTA/A53T α‐syn dTg mice were significantly lower than those of the CaMKIIα‐tTA sTg mice (Figure 6A). Here, CHAT is linked to Lewy body dementia.