Xia & He Publishing Inc. Jun 14 2025 Immediate-early genes (IEGs), including c-Fos, are integral to the brain's response to stimuli. Initially identified as a proto-oncogene, c-Fos is essential for neural activity, synaptic plasticity, and stress responses. While its transient expression supports memory formation in healthy brains, chronic overexpression in AD exacerbates neurotoxicity and cognitive decline. This review synthesizes findings from postmortem studies, animal models, and cell