Attention cortical responses to enlarged faces are reduced in underweight subjects: an electroencephalographic study

Abstract

Objective: A previous electroencephalographic (EEG) study has shown that obese subjects are characterized by reduced attention frontal responses to food images, thus raising the hypothesis of attention deficits associated with abnormal body weight (Babiloni et al., 2009a,b). In this line, here we tested the hypothesis of reduced attention cortical responses in underweight subjects.

Methods: EEG data were recorded in 16 normal-weight and 16 underweight subjects during an "oddball" paradigm. The subjects were given frequent (70%) and rare (30%) stimuli depicting faces (FACE), food (FOOD), and landscapes (CONTROL), and clicked the mouse after the rare stimuli. These stimuli depicted the same frequent stimuli graphically dilated by 25% along the horizontal axis. Cortical attention responses were probed by the difference between positive event-related potentials peaking around 400-500 ms post-stimulus for the rare minus frequent stimuli (P300). Low resolution electromagnetic source tomography (LORETA) estimated P300 sources.

Results: In the FACE condition, the amplitude of prefrontal (Brodmann area: BA10 and BA11) and tempo-parietal (BA19, BA20, BA21, BA22, BA36, BA37, BA39, BA40) sources was lower in the underweight than normal-weight subjects.

Conclusions: These results suggest that anterior-posterior cortical attention processes to face images declined in underweight subjects.

Significance: The present study motivates future research evaluating if this mechanism is related to a poor judgment about body shape.