Cognitive control in severe obese individuals: an ERPs study

Severe obesity has been associated with executive dysfunctions such as poor cognitive control during interference tasks. A source of behavioral studies showed lower cognitive control in obese compared to normal-weight when food-related stimuli are present, suggesting enhanced attention toward food (i.e. food-related attentional bias), which may reduce the efficiency of cognitive control. Here, cognitive control of interference in presence of food-related stimuli was assessed by means of event-related potentials (ERPs) and behavioral measures of cognitive control in severe obese individuals. Twenty-four obese and 28 normal-weight were evaluated in fasting state. Cognitive control in presence of food-related stimuli was investigated with a version of the Simon task modified with task-irrelevant food, object and neutral distractors. ERPs and reaction times (RTs) were registered in spatial corresponding (C) and non-corresponding (NC) conditions for each distractor. Larger Simon effect in presence of food-related distractors was found in the obese group. The N2 amplitude was higher in C compared to NC trials only in normal weight, whereas this effect was not present in the obese group. Longer P3 latency was found in obese compared to normal- weight. Attentional bias toward food interferes with cognitive control in severe obese individuals, supporting previous evidences for a food-related motor impulsivity. For the ERPs, the finding of higher N2 amplitude in conflict trials (NC) in normal-weight, but not in the obese group, suggests impaired conflict detection in the latter. Longer P3 latency observed in the obese may reflect a slowing down in information processing speed.