Non–cell autonomous pathogenesis in neurodegenerative diseases. This figure summarizes current evidence suggesting the contribution of apparently unaffected cell types in pathogenic mechanisms of neurodegenerative diseases, other than ALS. ¹(Choi et al., 2008; Streit et al., 2009), ²(Nakamura et al., 1990; Ekblom et al., 1993), ³(Liberatore et al., 1999), ⁴(Yazawa et al., 2005), ⁵(Shin et al., 2005), ⁶(Sapp et al., 2001), ⁷(Custer et al., 2006), ⁸(Raeber et al., 1997; Jeffrey et al., 2004), ⁹(Falsig et al., 2008), ¹⁰(Prinz et al., 2004).