Attentional Bias, "Cool" and "Hot" Executive Functions in Obese Patients: Roles of Body Mass Index, Binge Eating, and Eating Style.

PURPOSE/BACKGROUND: Obesity is recognized as an important risk factor for many chronic diseases and is a major health issue. The current study examined attentional bias to food and the "cool" (inhibitory control and mental flexibility) and "hot" (affective decision making) executive functions (EFs) in obese patients preparing for bariatric surgery. In addition to body mass index (BMI), this study examined the impact of the binge-eating tendency and eating styles. METHODS: The study population comprised 21 morbidly obese patients preparing to undergo bariatric surgery (BMI ≥30 kg/m) and 21 normal-weight controls (24 kg/m > BMI ≥ 18.5 kg/m). The Visual Probe Task was adopted to examine attentional bias toward food-related cues. The Stop-Signal Task and the Color Trails Test were used to assess inhibitory control and mental flexibility, respectively. The Iowa Gambling Task was administered to assess the affective decision making. RESULTS: (1) The obese patients showed poorer performances on cool EFs (for Color Trails Test, P = 0.016, ηp = 0.136; for Stop-Signal Task, P = 0.049, ηp = 0.093) and hot EF (for Iowa Gambling Task, normal controls showed progressed performance, P = 0.012, ηp = 0.077, but obese patients did not show this progress, P = 0.111, ηp = 0.089) compared with the normal controls; (2) participants with low binge-eating tendency had larger attentional biases at 2000 milliseconds than at 200 milliseconds on food-related cues (P = 0.003, ηp = 0.363); and (3) low-restrained participants exhibited attentional bias toward the low-calorie food cues, compared with the high-restrained group (P = 0.009, ηp = 0.158). CONCLUSIONS: The current study contributes to the development of a different therapeutic focus on obese patients and binge eaters.

Neural correlates of executive functions in patients with obesity.

Obesity is one of the most challenging problems in human health and is recognized as an important risk factor for many chronic diseases. It remains unclear how the neural systems (e.g., the mesolimbic "reward" and the prefrontal "control" neural systems) are correlated with patients' executive function (EF), conceptualized as the integration of "cool" EF and "hot" EF. "Cool" EF refers to relatively abstract, non-affective operations such as inhibitory control and mental flexibility. "Hot" EF refers to motivationally significant affective operations such as affective decision-making. We tried to find the correlation between structural and functional neuroimaging indices and EF in obese patients. The study population comprised seventeen patients with obesity (seven males and 10 females, BMI = 37.99 ± 5.40, age = 31.82 ± 8.75 year-old) preparing to undergo bariatric surgery. We used noninvasive diffusion tensor imaging, generalized q-sampling imaging, and resting-state functional magnetic resonance imaging to examine the neural correlations between structural and functional neuroimaging indices and EF performances in patients with obesity. We reported that many brain areas are correlated to the patients' EF performances. More interestingly, some correlations may implicate the possible associations of EF and the incentive motivational effects of food. The neural correlation between the left precuneus and middle occipital gyrus and inhibitory control may suggest that patients with a better ability to detect appetitive food may have worse inhibitory control. Also, the neural correlation between the superior frontal blade and affective decision-making may suggest that patients' affective decision-making may be associated with the incentive motivational effects of food. Our results provide evidence suggesting neural correlates of EF in patients with obesity.