TNF and Alzheimer disease: It regulates synaptic plasticity, microglial activation, astrocyte-induced synaptic strengthening, and glutamatergic transmission in the healthy CNS [343,344], while in pathological conditions, the copious amounts of TNF-α released by microglia mediate a chronic inflammation that leads to neuronal dysfunction and cognitive impairment [344], as seen in transgenic mouse models of AD [345].