Mecca AP, McDonald JW, Michalak HR, et al. - In this investigation involving 31 candidates [16 with amnestic mild cognitive impairment due to Alzheimer disease (AD) or mild AD dementia and 15 who were cognitively normal (CN)], researchers explored the connections between metabotropic glutamate subtype 5 receptors (mGluR5), seven-transmembrane G protein-coupled receptors located in excitatory synapses and in glial cells, binding in the hippocampus or association cortex with episodic memory performance and global function. According to findings, [¹⁸F]FPEB-PET showed declines in hippocampal mGluR5 binding in early AD. Quantification of mGluR5 binding in AD will improve understanding of AD pathogenesis and speed up the development of new biomarkers and treatments.