Melatonin is not your generic nootropic. In fact, the compound is best known for its role in helping the human race get some shut eye. It is naturally secreted by the pineal gland in the brain as the sun goes down, signaling and regulating sleep. Levels of melatonin are highest at night and dissipate during the day. Many Americans take melatonin as a sleep aid. The drug is available over the counter at most pharmacies. It is considered both natural and safe. Melatonin is the only hormone available in the United States without a prescription.
Beyond its abilities as a sleep aid, recent melatonin research highlights its neuroprotective abilities. To study its effectiveness, researchers turned, once again, to our rat friends. A group of rats were given bilateral intrahippocampal injection of Aβ1-42 or Aβ31-35, both of which cause cognitive impairment. They were then treated with a ten-day course of melatonin. Researchers examined the impact of the injections on both watermaze tasks – where rats are tasked with finding a stationary platform in a cold pool of water several times over the course of the study – and the rat’s theta rhythms – oscillatory patterns in the brain recorded by EEG scans. The results were clear: melatonin reversed the negative neurological impacts of the rat’s injections.
How might this information be applied to the human case? Amyloid-β proteins in the brain – examples of which were injected into the rats – are thought the be the main reason for memory loss in Alzheimer’s patients. Melatonin, then, might be a method of helping these people get their memories back. As is often the case, research is more devoted to curing diseases than identifying cognitive enhancement tools. Still, an understanding of how to fix impairment can go a long way towards understanding how to enhance cognitive ability.