This double-blind, controlled repeated measures within-subject design was conducted to examine the neural effects of green tea extract on human brain activation. Functional magnetic resonance imaging (MRI) was recorded while 12 healthy volunteers performed a working memory task following administration of 250 or 500 ml of either (1) a whey-based green tea containing soft drink or (2) a whey-based soft drink without green tea (control). A whole-brain analysis was followed by a priori-defined region of interest (ROI) analysis of the dorsolateral prefrontal cortex (DLPFC). Whole-brain analyses revealed no significant effects after correction for multiple comparisons. Using a ROI approach, green tea extract increased activation in the DLPFC relative to the control condition (P<0.001); this neural effect was related to green tea dosage. Green tea extract was not associated with any significant attenuation in regional activation relative to the control condition. These data suggest that green tea extract may modulate brain activity in the DLPFC, a key area that mediates working memory processing in the human brain. Moreover, this is the first neuroimaging study to suggest that functional neuroimaging methods provide a means of examining how green tea extract acts on the brain. Eur J Clin Nutr. 2012 Aug 29. PMID: 22929964
