title: Neural effects of green tea extract on dorsolateral prefrontal cortex.
abstract: OBJECTIVE
  Green tea is being recognized as a beverage with potential benefits for human health and cognitive functions. In vivo studies provide preliminary evidence that green tea intake may have a positive role in improving effects on cognitive functions. We aimed to examine the neural effects of green tea extract on brain activation in humans.
  
  
  METHODS
  Functional magnetic resonance imaging was recorded while 12 healthy volunteers performed a working memory task following administration of 250 or 500 ml of a milk whey based green tea containing soft drink or milk whey based soft drink without green tea as control in a double-blind, controlled repeated measures within-subject design with counterbalanced order of substance administration. A whole-brain analysis with a cluster-level threshold of P<0.001 (unadjusted) was followed by an a priori-defined region of interest (ROI) analysis of the dorsolateral prefrontal cortex (DLPFC) including a cluster-level threshold of P<0.05 and family-wise error (FWE) adjustment for multiple comparisons.
  
  
  RESULTS
  Whole-brain analyses revealed no significant effects after correction for multiple comparisons (FWE P<0.05). Using a ROI approach, green tea extract increased activation in the DLPFC relative to a control condition (FWE 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 control condition.
  
  
  CONCLUSIONS
  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 implicating that functional neuroimaging methods provide a means of examining how green tea extract acts on the brain.
authors.affiliation: University Hospital Basel, Medical Image Analysis Centre, University of Basel, Basel, Switzerland. sborgwardt@uhbs.ch
authors.forename: S
authors.initials: S
authors.lastname: Borgwardt
authors.forename: F
authors.initials: F
authors.lastname: Hammann
authors.forename: K
authors.initials: K
authors.lastname: Scheffler
authors.forename: M
authors.initials: M
authors.lastname: Kreuter
authors.forename: J
authors.initials: J
authors.lastname: Drewe
authors.forename: C
authors.initials: C
authors.lastname: Beglinger
mesh_terms: D000328:Adult; D001931:Brain Mapping; D028241:Camellia sinensis; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects*; D055815:Young Adult
chemical_list: D010936:Plant Extracts