title: Dietary fat induces sustained reward response in the human brain without primary taste cortex discrimination.
abstract: To disentangle taste from reward responses in the human gustatory cortex, we combined high density electro-encephalography with a gustometer delivering tastant puffs to the tip of the tongue. Stimuli were pure tastants (salt solutions at two concentrations), caloric emulsions (two milk preparations identical in composition except for fat content) and a mixture of high fat milk with the lowest salt concentration. Early event-related potentials (ERPs) showed a dose-response effect for increased taste intensity, with higher amplitude and shorter latency for high compared to low salt concentration, but not for increased fat content. However, the amplitude and distribution of late potentials were modulated by fat content independently of reported intensity and discrimination. Neural source estimation revealed a sustained activation of reward areas to the two high-fat stimuli. The results suggest calorie detection through specific sensors on the tongue independent of perceived taste. Finally, amplitude variation of the first peak in the event-related potential to the different stimuli correlated with papilla density, suggesting a higher discrimination power for subjects with more fungiform papillae.
authors: Perception Physiology Group, Food Consumer Interaction Department, Nestlé Research Center Lausanne, Switzerland.
authors: Hélène
authors: H
authors: Tzieropoulos
authors: Andreas
authors: A
authors: Rytz
authors: Julie
authors: J
authors: Hudry
authors: Johannes
authors: J
authors: le Coutre
keywords: calorie detection; electro-encephalography; gustatory event-related potentials; milk; salt