Neural effects of green tea extract on dorsolateral prefrontal cortex

Abstract

BACKGROUND/OBJECTIVES: 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. SUBJECTS/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 Po0.001 (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 Po0.05 and family-wise error (FWE) adjustment for multiple comparisons. RESULTS: Whole-brain analyses revealed no significant effects after correction for multiple comparisons (FWE Po0.05). Using a ROI approach, green tea extract increased activation in the DLPFC relative to a control condition (FWE Po0.001). 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.

Nutritional Aspects of Depression

“…Furthermore, green tea extract consisting of polyphenols, particularly catechins such as EGCG, caffeine, and theanine share an overlap in activity of at least one biochemical pathway, the N-methyl-D-aspartate receptor (NMDAR) pathway. Along this line, beneficial effects of green tea on cognitive functioning [151], in particular, on working memory processing at the neural system level suggested changes in short-term plasticity of parieto-frontal brain connections [152]. Additionally, evidence was found that the insulin sensitizer pioglitazone in a double-blind placebo-controlled study in 40 patients with major depression showed superiority over placebo during the course of the trial.…”

Green tea polyphenols and their potential role in health and disease

“…It influences cell survival through down-regulation of pro-apoptotic genes (He et al 2011) and promotes neural progenitor cell proliferation (Levites et al 2002a). Green tea extract has also been shown to enhance the neuronal activity in the prefrontal cortical areas of brain concerned with processing of working memory (Borgwardt et al 2012).…”

The effect of black tea on human cognitive performance in a cognitive test battery

“…The memory traces could be stabilized during the experimental sessions which helped BT consumers to retrieve the words [42]. A revious study [17] suggest that caffeine alters neuronal activity in the DLPFC (dorsolateral Pre-Frontal Cortex) during performance on a working memory task [38]. Additionally, our study showed that this effect might already had at caffeine dose of less than 70 mg.…”

“…Caffeine at a dose of 200-250 mg improves attention in visual search task [16]. Functional magnetic resonance imaging (fMRI) study reported that caffeine alters neuronal activity in the DLPFC (dorsolateral Pre-Frontal Cortex) on working memory task [17]. Caffeine also modulates neuronal activity [18].…”