10 research outputs found
Electro/magnetoencephalographic signatures of human brain insulin resistance
Human insulin action influences eating behavior, peripheral
metabolism and cognition. Detailed insights into the neuronal
processes related to human brain insulin action can be obtained
by direct measures of neuronal activity with
electroencephalography and magnetoencephalography.
Results of recent studies show that spontaneous, task and
stimulus related neuronal activity is modulated by insulin and that
several factors like increased body weight and body composition
can result in brain insulin resistance. Recent technological
advances even allow the investigation of human brain functions
in utero in relation to the metabolic status of the mother and
indicate an effect of the mother’s insulin sensitivity on the brain
function of the fetus. In conclusion, studies based on direct
neuronal measurements may help to determine the
developmental trajectory related to insulin action and resistance
Eating less or more – Mindset induced changes in neural correlates of pre-meal planning
Obesity develops due to an imbalance between energy intake and expenditure. Besides the decision about what to eat, daily energy intake might be even more dependent on the decision about the portion size to be consumed. For decisions between different foods, attentional focus is considered to play a key role in the choice selection. In the current study, we investigated the attentional modulation of portion size selection during pre-meal planning. We designed a functional magnetic resonance task in which healthy participants were directed to adopt different mindsets while selecting their portion size for lunch. Compared with a free choice condition, participants reduced their portion sizes when considering eating for health or pleasure, which was accompanied by increased activity in left prefrontal cortex and left orbitofrontal cortex, respectively. When planning to be full until dinner, participants selected larger portion sizes and showed a trend for increased activity in left insula. These results provide first evidence that also the cognitive process of pre-meal planning is influenced by the attentional focus at the time of choice, which could provide an opportunity for influencing the control of meal size selection by mindset manipulation
Oxytocin curbs calorie intake via food-specific increases in the activity of brain areas that process reward and establish cognitive control
Abstract The hypothalamic neurohormone oxytocin decreases food intake via largely unexplored mechanisms. We investigated the central nervous mediation of oxytocin’s hypophagic effect in comparison to its impact on the processing of generalized rewards. Fifteen fasted normal-weight, young men received intranasal oxytocin (24 IU) or placebo before functional magnetic resonance imaging (fMRI) measurements of brain activity during exposure to food stimuli and a monetary incentive delay task (MID). Subsequently, ad-libitum breakfast intake was assessed. Oxytocin compared to placebo increased activity in the ventromedial prefrontal cortex, supplementary motor area, anterior cingulate, and ventrolateral prefrontal cortices in response to high- vs. low-calorie food images in the fasted state, and reduced calorie intake by 12%. During anticipation of monetary rewards, oxytocin compared to placebo augmented striatal, orbitofrontal and insular activity without altering MID performance. We conclude that during the anticipation of generalized rewards, oxytocin stimulates dopaminergic reward-processing circuits. In contrast, oxytocin restrains food intake by enhancing the activity of brain regions that exert cognitive control, while concomitantly increasing the activity of structures that process food reward value. This pattern points towards a specific role of oxytocin in the regulation of eating behaviour in humans that might be of relevance for potential clinical applications