This rat study examined acute (1-week) and chronic (10-week) exposure to 2100 MHz radiofrequency radiation (3G UMTS-like) and assessed auditory mismatch negativity (MMN) alongside biochemical and histological brain measures. The abstract reports that acute exposure was associated with reduced MMN-related electrophysiological parameters and changes in GluR2 and GFAP with observed brain ultrastructural alterations. Chronic exposure showed opposite protein trends and enhanced MMN parameters versus chronic controls, and lipid peroxidation was not significantly different.