Food intake habits and preference affects the activity of medial frontal cortex during eating; functional near-infrared spectroscopy is potential biosensor for appetite study.

Even if they have no dementia, some elderly people find it difficult to imagine the food they may want to eat. However, research into treatments for anorexia in elderly people has not progressed sufficiently due to the lack of a method that can easily measure brain function in clinical settings. In this study, we aim to clarify the relationship of food-dependent medial prefrontal cortex (MPFC) activity with food preference and intake frequency by functional near-infrared spectroscopy (fNIRS) to determine ways to treat the appetite loss and have difficulty in explain what they want to eat. For this purpose, we firstly establish the methodology using young participants experiment. All young participants were asked about their food preferences and intake frequency using a questionnaire, and they were instructed to look and then eat the control dish (CD: typical Japanese home-cooked meal) and their preferred dish (PD: each participant purchased the dish themselves on the day of the experiments) on separate days, and activity of MPFC in each participant was recorded by fNIRS. We found that activity of MPFC during "just-looking" and "eating" were affected by food intake habits and preference. Especially, activity of MPFC during CD eating was affected by food preference (has dislike food or not). We concluded that the activity of MPFC during eating of dishes varies depending on the food intake habits and fNIRS could be a potential technique for estimating such activity.