Association of the FTO (rs9939609) gene with the neural correlates of working-memory based modulation of attention to food

Food-related stimuli in the environment attract attention because of their association with rewarding consequences. However, evidence suggests that cognitive processing of food stimuli can also influence attention via top-down control. We investigated neural responses when holding a food or non-food item in working-memory (WM) and the influence of obesity-risk gene FTO in 15 subjects. Participants were presented with a cue (food or non-food) to hold in WM. Subsequently, they had to respond to a target and ignore a distracter, both paired with a food or non-food item. Behavioural performance was more strongly affected by food cues than non-food cues held in memory (ηp2=0.215). Participants with the FTO risk allele showed a strong interaction between memory and selective attention (p<0.001, ηp2=0.617). Neuroimaging data showed an increased activation of fronto-parietal attention network when a non-food cue (vs. food) was held in WM, whereas a food-cue enhanced right hippocampal and caudate activation but only when with the target was paired with the cue (p<0.05 FWE-corrected). The latter was associated with the T-allele. Additionally, a group of 17 subjects performed the same behavioural test. Here, subjects were also faster in identifying the target (p<0.005, ηp2=0.358) when holding a food-cue in WM, however the FTO risk allele had medium effect (ηp2=0.076). The data suggest that when holding food items in WM, attention is strengthened; this is consistent with the idea that food items have a high motivational salience. This effect is modulated by the obesity-risk gene FTO, suggesting that top-down control of attention via WM might be a target for intervention in obesity.