TNF and Cognitive impairment: Changes in hippocampal levels of p-ERK have been linked to cognitive impairment in a mouse model of Alzheimer’s disease [18], and p-ERK appears to induce production of pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β), in animal models of cognitive deficits [19].