Still another study indicates that green tea has an enhancing effect on cognitive function. Pert the article:
In a new study, the researcher teams of Prof. Christoph Beglinger from the University Hospital of Basel and Prof. Stefan Borgwardt from the Psychiatric University Clinics found that green tea extract increases the brain's effective connectivity, meaning the causal influence that one brain area exerts over another. This effect on connectivity also led to improvement in actual cognitive performance: Subjects tested significantly better for working memory tasks after the admission of green tea extract.
The findings have been published in the journal, Psychopharmacology.
The experimenters used green tea extract so I don't think caffeine was involved in the study.
Good to know, thanks.