Figure 1 shows how the changes of eNOS and iNOS activity can affect human cognitive functions. Animal model studies pointed to the fact that the modulation of NO levels via NOS activity, for example, by administration of polyphenols, may affect aging and dementia [33], memory deficits and long-term memory [34], spatial working memory [35], and performance in cognitive tasks relating to learning and memory as well [36]. The gene discussed is NOS2; the disease is dementia.