Regions of the human brain affected during a liquid-meal taste perception in the fasting state: a positron emission tomography study

Background: The sensation of taste provides reinforcement for eating and is of possible relevance to the clinical problem of obesity. Objective: Positron emission tomography (PET) was used to explore regions o f the brain that were preferentially affected during the taste perception o f a liquid meal by 11 right-handed, lean men in the fasting state. Design: After subjects had fasted for 36 h, 2 measurements of regional cere bral blood flow (rCBF) obtained immediately after subjects retained and swa llowed 2 mt of a flavored liquid meal (the taste condition) were compared w ith 2 measurements of rCBF obtained immediately after subjects retained and swallowed 2 mt of water (the baseline condition). Results: Compared with the baseline condition, taste was associated with in creased rCBF (P < 0.005) in the left dorsolateral prefrontal cortex and sup erior temporal gyrus; the right ventrolateral prefrontal cortex, supramargi nal gyrus, and anterior thalamus; and bilaterally in the hippocampal format ion, posterior cingulate, midbrain, occipital cortex, and cerebellum. Taste was also associated with decreased rCBF (P < 0.005) in the right dorsolate ral prefrontal cortex, superior temporal gyrus, and supplementary motor are a, and bilaterally in the medial prefrontal cortex and inferior parietal lo bule. Conclusions: This exploratory study provides additional evidence that the t emporal cortex, thalamus, cingulate cortex, caudate, and hippocampal format ion are preferentially affected by taste stimulation. The asymmetric patter n of activity in the dorsolateral prefrontal cortex and superior temporal g yrus may contribute to the taste perception of a liquid meal perceived as p leasant. Additional studies are required to determine how these regions are affected in patients with obesity or anorexia.