neuro imaging

Shared and differential neurocognitive mechanisms in obesity and binge eating disorder from adolescence to adulthood: an attempt to improve prediction of clinical outcome (Dr. Lorenz Deserno)

Individuals suffering from obesity and binge eating disorder (BED) repeat health-damaging decisions, which is associated with enormous subjective suffering and high economic burden for health systems. A key problem is that clinicians treating these patients so far do not have reliable and objective tools available to predict clinical outcome. This represents a severe disadvantage as both disorders have high rates of onset in adolescence and early adulthood leading to long and detrimental disease trajectories. Very recently, neurocognitive research utilizing task-based functional neuroimaging has started to understand the deficits of these patients in making flexible goal-directed decisions.

Brain dopamine D1 receptor in human gastric bypass responders versus non-responders (Prof. Dr. Swen Hesse)

Peripheral signals influence not just homeostatic, but also hedonic aspects of feeding via gut-brain pathways, and thus play an important role in the motivation to eat. A key structure at the interface between cortical (i.e. prefrontal) networks and afferent information is the central dopamine (DA) system. It integrates sensory infor-mation, which is processed in mesolimbic and nigrostriatal reward-related circuits. Recent evidence suggests that these signals contribute to changes in striatal DA transmission in obesity resulting in altered perception of the rewarding properties of dietary fat intake after bariatric (Roux-en-Y gastric bypass, RYGB) surgery.

Specific impact of hypothalamic G-protein-signaling cascades on appetite (Dr. Doreen Thor)

In order to find new ways to influence the regulation of appetite in humans, it is important to understand the underlying mechanisms. Here certain brain regions (neurons in the hypothalamus) are crucial, which regulate the energy balance (homeostasis) and the sensation of hunger. In this study special ways of neuronal signaling (signaling cascade) are being examined.

Cholinergic network modulation in disinhibited eating behavior (Prof. Dr. Swen Hesse)

Overweight and obesity are partly due to a lack in regulating one’s eating behavior. This study examines the mechanisms of uncontrolled eating behavior. The neuro-transmitter acetylcholine and further transmitters as well as certain brain regions are crucial for the regulation od appetite and eating. With brain imaging via the combined positron-emission- and magnetic-resonance-tomography these brain regions and transmitters are being examined in study participants – with and without food stimuli. In addition the probands fill out questionnaires with reference to eating behavior. The results of this research could be a first step toward novel pharmaceutical or behavioral treatment approach, which can improve the regulation of eating behavior in obese patients.

Instrumental learning and Pavlovian to instrumental transfer in obesity (Prof. Dr. Jane Neumann, completed)

Instrumental learning and behavior mean adequate behaviors e. g. a healthy food choice, and the ability to react appropriately in a given situation. In obesity there may be a deficit in instrumental learning and behavior. The so called “Pavlovian-to-Instrumental Transfer” (PIT) is the influence of positive and negative stimuli from the environment onto the instrumental behavior. This project examines obesity- and gender-related alterations in instrumental learning and the influence of stimuli on instrumental behavior. The examinations will look at the behavioral and neuronal aspects. Normal- and overweight study participants do tests, in which they learn the association of special stimuli with behaviors and reward.

Retraining Automatic Action Tendencies in Obesity (Dr. Annette Horstmann)

In obese people paradoxical behaviors comparable to those in drug addicts are often observed. These behaviors are unfavorable and unhealthy, they occur although the people affected know the negative consequences. Using functional magnetic resonance imaging (fMRI) the role of the brain in such mostly automatic behaviors is being investigated. In addition, the inversion of these behaviors is attempted by the patients’ unlearning through behavioral training. This and the accompanying plastic changes in the brain are also examined by fMRI.

Neurobiology of conditioning to primary reinforcers and its role in obesity (Dr. Annette Horstmann)

This study should clarify the influence of habitual (conditioned, automatic) behavior on decision making in obesity. Obese people mostly react automatically with increased food intake to the mere view, the smell and the taste of food, regardless of their hunger and energy needs (their homeostatic status). Using functional magnetic resonance imaging (fMRT) the response to these stimuli in obese and normal weight subjects and their impact on eating habits should be verified. Understanding these factors is important in order to improve weight reduction treatments and to recognize and dismantle for example behavioral barriers.

Imaging brain serotonin transporters as an integrative part of the microbial gut-brain axis and homeostatic control – a feasibility study (Prof. Dr. Swen Hesse, completed)

The gastro-intestinal system and the brain are connected neuronaly. They influence each other and in consequence also the energy balance, mood and thinking. An important role plays the transmitter serotonin. Especially the type of gut microbiome is essential for the communication between gut and brain. This study examines for the first time the coherence between microbiome and a substance which activates serotonin, the serotonin transporter (SERT). Beside the microbiome, certain brain areas and functions and metabolic active hormones are being examined. The aim is to characterize and examine the interactions in obesity.

Biasing reward-based decision making towards advantageous choices in Obesity (Dr. Annette Horstmann, abgeschlossen)

The study examines the effect of pleasant, appetizing as opposed to unpleasant visual, olfactory, and taste stimuli on the decision making of normal weight and obese participants. The focus in this trial is on the role of active networks in the brain and nerve system. Through the combination of behavior tests and visual imaging techniques it is possible to directly analyze the differences in the brain of normal and overweight participants. These differences can be the cause the different behavioral effects.

Habitual vs. Goal-Directed Behavioural Control in Obesity (Dr. Annette Horstmann, completed)

Studies suggest that obese people tend to actions and behaviors that lead to quick rewards. This can promote overweight if this also applies to the eating behavior. The researchers examine which role the brain plays in reward orientated, and respectively more controlled behavior. Thereto the reactions of the brain in over- and normal-weight participants are measured in image, smell and taste tests. The tests are associated with learning and decision tasks, because a different reaction to such test stimuli could explain different behaviors. The aim is to better understand the neurobiological basis of decision making. This may be helpful to develop special therapies or behavior trainings.

Impact of bariatric surgery on central serotonin- & norephinephrine transporter availability in obese subjects using Positron Emission Tomography (PET) & selective radio-labelled marker before & 6 months after surgery (Prof. Dr. Hesse, completed)

The study examines the effects of bariatric surgery on the availability of certain messenger substances (neurotransmitter) in the brain that apparently play an important role in adiposity. The distribution of serotonin- and norepinephrin transporter is immediately investigated before the surgical intervention and six months after by means of the Positron Emission Tomography (PET). The results are compared with examinations among slim controls and obese patients which has undergone non- operatively treatment.

The role of autophagy in peripheral nervous system and in the adipose tissue of WOKW rats with the metabolic syndrome (Joanna Kosacka, PhD, completed)

This study examines in animal models how special metabolic diseases lead to a protecting mechanism against diabetes and peripheral neurodegeneration (nerve damage). Metabolic diseases like the metabolic syndrome normally lead to a higher prevalence of diabetes and neuro degeneration (peripheral neuropathy). This study examins, if the proliferation of immune cells such as macrophages and T-cells and an increased autophagy (degrading of cell components) in the peripheral neurons of the spinal ganglions or fat cells contribute to the protective mechanism. The research can be the basis for further human studies.

The influence of bariatric surgery on functions and structures of brain regions, which control eating behavior (PD Dr. Burkhard Pleger, completed)

This study examines which effect the drastic weight loss after bariatric surgery has on the brain regions, that are responsible for eating behavior. Via Magnet-Resonance-Tomography (MRT) patients will be examined in the course of four years. Additionally, the MRT imaging will be used to predict the success or failure of bariatric surgery.

Norepinephrine transporter PET imaging in obesity (Prof. Dr. Swen Hesse, completed)

In this study researchers examine if and to what degree dysfunctions of central neurotransmitters, such as the “happiness hormone” Serotonin, are responsible for the emergence of eating disorders or adiposity. With the so called Positron Emission Tomography (PET) these processes can be visualized and measured.

COREDEC: Computational modelling of reward-related and decision-making processes in patients with obesity and eating disorder (Dr. Jane Neumann, completed)

The main question of the study is whether obese persons have learnt to decide if and what to eat differently than persons of normal weight. Scientists also try to find out which processes in the brain are responsible for these mechanisms of decision making, and how they can be influenced and be made visible via diagnostic means of imaging.

Assessment of brain structure and functional connectivity in obesity (Prof. Dr. Arno Villringer, completed)

The study tests whether there are recognizable patterns in the brain structure, which are related to the causes or the secondary diseases of adiposity. These patterns could help to develop a therapy of obesity.