Technical Abstract: We have shown that whole, crude blueberry (BB) extracts are able to reverse several parameters of brain aging (e.g., deficits in cell communication) as well as age-related motor and cognitive deficits when fed to rats from 19-21 months of age. These effects appear to be the result of compounds (polyphenolics) that enhance the survivability of the plant, possibly through direct effects on brain signaling or indirectly through their antioxidant and anti-inflammatory properties. However, given the complex mixtures of phytochemicals in fruits, it is difficult to discern from a crude BB extract the contribution of non-polyphenolic compounds to these effects. Thus, the present study examined 3 different BB-derived diets, all equated on phenolic level, to determine whether the effects observed with the whole, crude BB extract are indeed due to polyphenolics or whether other compounds were contributing to the age-related improvements in behavior. Old (19 mo) F344 rats were fed a control diet or one with 5.4% crude BB extract (as before), a 2% pre-C18 column BB extract, or a 0.1% post-C18 column semi-purified BB extract (a mixture of only BB phenolics with the sugars and organic acids removed) for 8 weeks prior to motor and cognitive testing. Results showed that only the crude BB extract diet improved rotarod performance, while all three BB-derived diets improved working memory in the MWM. Therefore, phenolics are important components in the beneficial effects of BBs on age-related improvements in cognition, but other compounds may play a role in motor improvements. Future examinations of the specific phenolic families found in each extract will determine the most effective large family of compounds that may be producing these effects. We hope to further assess the mechanisms involved in BBs beneficial effects by examining the improvements with each BB extract on signaling parameters in these rats.