Intriguingly, defects in these forms of plasticity are observed in neurological disease models, which are associated with elevated levels of Arc, (e.g., Fragile X syndrome, Angelman syndrome, and Alzheimer’s disease) (Auerbach and Bear, 2010, Greer et al., 2010, Megill et al., 2015, Pastuzyn and Shepherd, 2017, Wu et al., 2011). Here, ARC is linked to fragile X syndrome.