In order to investigate whether the increased mGluR5 level in the DLB and PD cases and in the alpha-syn tg mice was associated with a concomitant increase in the levels of downstream signaling components, levels of total and phosphorylated ERK, Elk–1 and CREB were examined in the cytoplasmic and membrane fractions from the frontal cortex. Here, CREB1 is linked to Parkinson disease.