Oxiracetam is one of the racetams, and is structurally different from piracetam due to a single hydroxyl group. It is also used for nootropic purposes such as enhancing learning in students or preventing against cognitive decline. Like all other racetams, it is a synthetic molecule that is not found in food sources or in nature.
When looking at the evidence for oxiracetam at this point in time it seems to have a fair bit of human evidence for reducing the rate of organic cognitive decline (a natural loss in cognition that occurs during the aging process that is not associated with any disease state) and with dementia, yet the lone study in persons with Alzheimer's showed no apparent benefit with oxiracetam supplementation. When it does aid in cognitive decline, it is somewhat comparable in potency to Alpha-GPC and seems to be slightly more potent than piracetam.
There is currently no evidence to support cognitive enhancement of oxiracetam in young humans with no cognitive impairment looking to increase memory formation.
When looking at animal evidence, oxiracetam appears to very reliably and potently prevent amnesia induced by a variety of anti-cholinergic or anti-glutaminergic compounds (injections of 3-30mg/kg in rats pretty much normalizing memory formation). It has been implicated in increasing memory formation in otherwise healthy and young rats/mice with no apparent cognitive impairment (suggesting that it can be used as a nootropic) but it appears to require at least a five day loading period.
Oxiracetam is a positive AMPA modulator similar in mechanism and potency (but not binding site) to both piracetam and aniracetam but may have an additional benefit of increasing glutamate, acetylcholine, and D-aspartic acid release from activated but not resting neurons. This two-fold sequence (enhancing glutamate release and then positively modulating one of the receptors it signals through) ultimately increases metabolic activity in neuronal cells and memory formation.