The repeated circling behavior in APP/PS1 mice was also reminiscent of topographical disorientation, which is common in human patients affected by mild cognitive impairment progressing to AD (Huang et al., 2002; Trivedi et al., 2006; Seo et al., 2007; Whitwell et al., 2007; Desikan et al., 2008). The gene discussed is APP; the disease is Alzheimer disease.