C5AR1 and Mental deterioration: To further elucidate the role of C5a–C5aR1 signaling in amyloid-associated cognitive decline, and to expand on our previous behavioral studies examining the role of C5a–C5aR1 signaling on cognitive decline in the Arctic mouse, we crossed the Arctic mouse to a model that overexpresses C5a under the control of the glial fibrillary acidic protein (GFAP) promoter and tested spatial memory with the object location memory (OLM) test [18, 21].