How are overweight and obesity associated with reinforcement learning deficits? A systematic review.

Reinforcement learning (RL) refers to the ability to learn stimulus-response or response-outcome associations relevant to the acquisition of behavioral repertoire and adaptation to the environment. Research data from correlational and case-control studies have shown that obesity is associated with impairments in RL. The aim of the present study was to systematically review how obesity and overweight are associated with RL performance. More specifically, the relationship between high body mass index (BMI) and task performance was explored through the analysis of specific RL processes associated with different physiological, computational, and behavioral manifestations. Our systematic analyses indicate that obesity might be associated with impairments in the use of aversive outcomes to change ongoing behavior, as revealed by results involving instrumental negative reinforcement and extinction/reversal learning, but further research needs to be conducted to confirm this association. Hypotheses regarding how obesity might be associated with altered RL were discussed.

Unusual localizations of hydatid cysts: a rare case report from Syria.

Hydatid disease (HD) is an infection with the metacestode stage of the tapeworm Echinococcus. It is commonly seen in South America, The Middle East, Eastern Mediterranean, Africa and China. Hydatid cysts usually affect the liver followed by the lungs. Involvement in other organs has been reported. However, in the majority of the cases, cysts are localized in one organ or one region. We report a rare case of a 36-year-old woman who presented to the hospital in Syria with long-standing history of non-specific abdominal pain. Computerized tomography showed several hydatid cysts in the liver, spleen, left lung, mediastinum (adjacent to the aortic arch), both breasts and above the right gluteal muscles.