The effect of satiation on cognitive and reward processes

Natural satiation attenuates activity in reward-related brain regions and increases activity in cognitive control areas, but little is known about the specific underlying cognitive processes. This study assessed the effect of satiation on reward, attention, memory and behavioural control mechanisms. Twenty-five participants (8 male, BMI 21.9kg/m2, age 21.3y) were tested in a counter balanced within-subject design. All participants visited the laboratory twice at lunchtime. In the satiated condition participants consumed a lunch of cheese sandwiches before completing a battery of reward and cognitive tasks, measuring both behavioural and BOLD-fMRI responses. In the pre-meal condition lunch was provided after testing. Initial analyses showed that food images were rated as more appealing in the pre-meal condition (p<0.001), whereas the value for non-food stimuli was not significantly different between conditions (p=0.37). When satiated, choice of a delayed food reward was increased (p=0.01), whereas there was no effect of satiation on monetary reward choice (p=0.76). Memory for food, emotional, and neutral words in a free recall was unaffected by nutritional state (p=0.52). These initial results confirm that reward and cognitive processes are affected by satiation. The next step is to further investigate the effect of satiation on inhibition, attention and related brain responses, and to explore the interplay between these hedonic and cognitive processes to improve our understanding of the behavioural and neural mechanisms that mediate everyday food consumption.