Eigenpoll : Cognitive improvement : Pyrroloquinoline quinone 

PQQ is a neuroprotective compound that has been shown in a small number of preliminary studies to protect memory and cognition in aging animals and humans. It has been shown to reverse cognitive impairment caused by chronic oxidative stress in animal models and improve performance on memory tests.[19] PQQ supplementation stimulates the production and release of nerve growth factors in cells that support neurons in the brain, a possible mechanism for the improvement of memory function it appears to produce in aging humans and rats.