PSEN1 and Cognitive impairment: Supporting the idea that mGluR‐LTD may be affected at early stages of the disease are findings showing that accumulation of amyloid beta (Aβ) oligomers is associated with excessive activation of mGluR5 signalling and that pharmacological antagonism of mGluR5 ameliorates cognitive impairments in the APP/PS1 mouse (Hamilton et al., 2016; Renner et al., 2010; Um et al., 2013).