Effect of Consumption on Cognitive Processes

To get a better understanding of the interaction between metabolism, neural responses, cognitive processes and appetite the investigaters will examine the effect of food consumption on cognitive processes. The investigaters will look at the effect of satiation on cognitive performance on both a behavioural and neuronal level. In this study participants will undergo functional magnetic resonance imaging (fMRI) measurements while performing a food reward and inhibition task, and in addition perform a memory, working memory and delay discount task, once when hungry and once when full.

Human eating behaviour is a very complex process. It has been well established that food intake and choice are influences by nutritional composition of the food and their reward values. However recent work suggests that cognitive processes such as memory, attention, and inhibition influence food choices. Thinking about food can lead to increased attention to food cues, which can result in a greater chance of actual food consumption. Additional manipulation of attention effects memory and snack intake. It has been suggested that memory inhibition plays a critical role in suppression of food-related information when satiated to prevent overeating. These results underpin the interaction between cognitive processes and internal state and its effect on appetite. Although it has been widely studied what the effect of satiation is on reward and even which brain regions are associated with food intake, for both homeostatic and hedonic eating, the direct effect of consumption on cognitive processes and the related brain processes are rather unknown.

In this study participants will be asked to come to a research facility twice (within-design). Once the particpant will undergo all the tasks when hungry and receive a lunch at the end of the study-day (hungry session), and once the subject will first receive a lunch and then perform all the tasks (satiated session). Upon arrival subjects will fill in their appetite and mood ratings, followed by a break or a lunch (depending on the session). After the 25-min break/lunch the subject will be placed in the scanner. First the particpants neural responses will be measure while performing an inhibition task, here subjects will complete a go-no/go task; the particpant either has to go (press) when seeing a toiletry or stationary item, or not go (withhold pressing) when seeing a food or sports item. Second a resting state fMRI measurement will be performed. Third subjects will see food and non-food items, which the particpant has to rate on their appeal. Last an anatomical scan will be run. When out of the scanner subjects will undergo several cognitive computerized tasks, a word recall task, a working memory task (measuring the top-down guidance of attention to food stimuli via working memory) and a delay discount task. At last subjects will get lunch (when receiving a break at the start) or a break (when consuming food at arrival).

Eligibility Criteria:
Inclusion Criteria:

* Healthy subjects
* Age 18-45 years at start of the study
* Right-handedness (including left-handers could bias the results because of the laterality of brain functions)
* Ability to give informed consent
* Fluent English speaking
* Willingness to be informed about chance findings of pathology

Exclusion Criteria:

* Subjects who have a non-removable metal object in or at their body, such as, for example: Heart pace-maker, artificial heart valve, metal prosthesis, implants or splinters, non-removable dental braces
* Tattoos, that are older than 15 years
* Claustrophobia
* Pathological hearing ability or an increased sensitivity to loud noises
* Lack of ability to give informed consent
* Operation less than three months ago
* Acute illness or infection during the last 4 weeks
* Cardiovascular disorders (e.g., hypertrophic cardiomyopathy, long QT syndrome)
* Moderate or severe head injury
* Eating disorders
* No metabolic (e.g. metabolic disorder, diabetes, insulin resistance), psychological (e.g. depression) or neurological (e.g. epilepsy, headache disorder, multiple sclerosis, traumatic brain injuries) diseases or medication in relation to these diseases.
* Current weight loss regimens, or more then 5kg weight loss in the last 3 months
* Smoking
* Current pregnancy or breastfeeding
* Current or past history of drug or alcohol dependency - alcohol consumption exceeding 12 units a week
* Food allergies (e.g. peanut allergy lactose and gluten intolerance) or vegetarian/vegan diet
* Disliking the study lunch