Member Login

Login to your account

Username *
Password *
Remember Me

Selective Insulin Resistance in Homeostatic and Cognitive Control Brain Areas in Overweight and Obese Adults

Stephanie Kullmann, Martin Heni, Ralf Veit, Klaus Scheffler, Jurgen Machann, Hans-Ulrich Haring,
Andreas Fritsche, and Hubert Preissl

Diabetes Care 2015;38:1044–1050

Due to strong associations with numerous conditions, such as type 2 diabetes and cardiovascular disease, obesity has become a major public health concern. Obesity is associated with peripheral insulin resistance in many organs, such as muscle, liver, and adipose tissue. However, only recently was the brain identified as an insulinsensitive organ regulating food intake. In humans, the central nervous effects of insulin still remain ill defined. In search of new insights in the pathogenesis of obesity and brain insulin resistance, modern neuroimaging techniques have emerged as valuable tools to investigate insulin action in the human brain.

 read the full article

So Many Brands and Varieties to Choose from: Does This Compromise the Control of Food Intake in Humans?

Charlotte A. Hardman, Danielle Ferriday, Lesley Kyle, Peter J. Rogers, and Jeffrey M. Brunstrom

PLoS ONE 10(4):1-17 (2015)

The recent rise in obesity is widely attributed to changes in the dietary environment (e.g., increased availability of energy-dense foods and larger portion sizes). However, a critical feature of our “obesogenic environment” may have been overlooked - the dramatic increase in
“dietary variability” (the tendency for specific mass-produced foods to be available in numerous varieties that differ in energy content). In this study we tested the hypothesis that dietary variability compromises the control of food intake in humans

read the full article

Energy-dense snacks can have the same expected satiation as sugar-containing beverages

Ashley A. Martin, Liam R. Hamill, Sarah Davies, Peter J. Rogers and Jeffrey M. Brunstrom

Appetite 95: 81-88 (2015)

Sugar-sweetened beverages (SSBs) are thought to be problematic for weight management because energy
delivered in liquid form may be less effective at suppressing appetite than solid foods. However,
little is known about the relative ‘expected satiation’ (anticipated fullness) of SSBs and solid foods. This is
relevant because expected satiation is an important determinant of portion selection and energy intake.

read the full article

Expected Satiety: Application to Weight Management and Understanding Energy Selection in Humans

Ciarán G. Forde, Eva Almiron-Roig and Jeffrey M. Brunstrom

Current Obesity Reports  4:131–140 (2015)

Recent advances in the approaches used to quantify expectations of satiation and satiety have led to a better understanding of how humans select and consume food, and the associated links to energy intake regulation. When compared calorie for calorie some foods are expected to deliver several times more satiety than others, and multiple studies have demonstrated that people are able to discriminate between similar foodsreliably and with considerable sensitivity.

read the full article

In search of flavour-nutrient learning. A study of the Samburu pastoralists of North-Central Kenya

Jeffrey M. Brunstrom, Peter J. Rogers , Kevin P. Myers and Jon D. Holtzman

Appetite 91:  415–425 (2015)

Much of our dietary behaviour is learned. In particular, one suggestion is that ‘flavour-nutrient learning’
(F-NL) influences both choice and intake of food. F-NL occurs when an association forms between
the orosensory properties of a food and its postingestive effects. Unfortunately, this process has been difficult
to evaluate because F-NL is rarely observed in controlled studies of adult humans. One possibility
is that we are disposed to F-NL. However, learning is compromised by exposure to a complex Western
diet that includes a wide range of energy-dense foods.

read the full article

Acute Stress Impairs Self-Control in Goal-Directed Choice by Altering Multiple Functional Connections within the Brain’s Decision Circuits

Silvia U. Maier, Aidan B. Makwana, and Todd A. Hare.

Neuron 87 :621–631, 2015

Important decisions are often made under stressful circumstances that might compromise self-regulatory behavior. Yet the neural mechanisms by which stress influences self-control choices are unclear. We investigated these mechanisms in human participants who faced self-control dilemmas over food reward while undergoing fMRI following stress. We found that stress increased the influence of
immediately rewarding taste attributes on choice and reduced self-control.  This choice pattern was accompanied by increased functional connectivity between ventromedial prefrontal cortex (vmPFC) and amygdala and striatal regions encoding tastiness.Furthermore, stress was associated with reduced connectivity between the vmPFC and dorsolateral prefrontal cortex regions linked to self-control success. Notably, alterations in connectivity pathways could be dissociated by their differential relationships with cortisol and perceived stress.
Our results indicate that stress may compromise self-control decisions by both enhancing the impact of immediately rewarding attributes and reducing the efficacy of regions promoting behaviors that are consistent with long-term goals.

read the full article


Food reward. What it is and how to measure it

Peter J. Rogers; Charlotte A. Hardman

Appetite Vol.90 1-15 July 2015

We investigated the contribution of hunger and food liking to food reward, and the relationship between food reward and food intake. We defined liking as the pleasantness of taste of food in the mouth, and food reward as the momentary value of a food to the individual at the time of ingestion. Liking and food reward were measured, respectively, by ratings of the pleasantness of the taste of a mouthful, and ratings of desire to eat a portion, of the food in question. Hunger, which we view as primarily the absence of fullness, was rated without food being present. Study 1 provided evidence that hunger and liking contribute independently to food reward, with little effect of hunger on liking. Food intake reduced liking and reward value more for the eaten food than uneaten foods. The results were ambiguous as to whether this food-specific decline in reward value (‘sensory-specific satiety’) involved a decrease in ‘wanting’ in addition to the decrease in liking. Studies 2 and 3 compared desire to eat ratings with work-for-food and pay-for-food measures of food reward, and found desire to eat to be equal or superior in respect of effects of hunger and liking, and superior in predicting ad libitum food intake. A further general observation was that in making ratings of food liking participants may confuse the pleasantness of the taste of food with the pleasantness of eating it. The latter, which some call ‘palatability,’ decreases more with eating because it is significantly affected by hunger/fullness. Together, our results demonstrate the validity of ratings of desire to eat a portion of a tasted food as a measure of food reward and as a predictor of food intake.

read the full article

Resting-state functional connectivity of the human hypothalamus

Stephanie Kullmann,Martin Heni, Katarzyna Linder,Stephan Zipfel, Hans-Ulrich Häring,Ralf Veit,
Andreas Fritsche, and Hubert Preissl

Human Brain Mapping 35:6088–6096 (2014)

The hypothalamus is of enormous importance for multiple bodily functions such as energy homeostasis. Especially, rodent studies have greatly contributed to our understanding how specific hypothalamic subregions integrate peripheral and central signals into the brain to control food intake. In humans, however, the neural circuitry of the hypothalamus, with its different subregions, has not been delineated. Hence, the aim of this study was to map the hypothalamus network using resting-state functional connectivity (FC) analyses from the medial hypothalamus (MH) and lateral hypothalamus (LH) in healthy normal-weight adults (n = 49). Furthermore, in a separate sample, we examined differences within the LH and MH networks between healthy normal-weight (n = 25) versus overweight/obese adults (n = 23). FC patterns from the LH and MH revealed significant connections to the striatum, thalamus, brainstem, orbitofrontal cortex, middle and posterior cingulum and temporal brain regions. However, our analysis revealed subtler distinctions within hypothalamic subregions. The LH was functionally stronger connected to the dorsal striatum, anterior cingulum, and frontal operculum, while the MH showed stronger functional connections to the nucleus accumbens and medial orbitofrontal cortex. Furthermore, overweight/obese participants revealed heightened FC in the orbitofrontal cortex and nucleus accumbens within the MH network. Our results indicate that the MH and LH network are tapped into different parts of the dopaminergic circuitry of the brain, potentially modulating food reward based on the functional connections to the ventral and dorsal striatum, respectively. In obese adults, FC changes were observed in the MH network.

read the full article

GLP-1 Receptor Stimulation of the Lateral Parabrachial Nucleus Reduces Food Intake: Neuroanatomical, Electrophysiological, and Behavioral Evidence

Endocrinology. Nov 2014; 155(11): 4356–4367.

Jennifer E. Richard,* Imre Farkas,* Fredrik Anesten,* Rozita H. Anderberg, Suzanne L. Dickson, Fiona M. Gribble, Frank Reimann, John-Olov Jansson, Zsolt Liposits, and Karolina P. Skibicka

The parabrachial nucleus (PBN) is a key nucleus for the regulation of feeding behavior. Inhibitory inputs from the hypothalamus to the PBN play a crucial role in the normal maintenance of feeding behavior, because their loss leads to starvation. Viscerosensory stimuli result in neuronal activation of the PBN. However, the origin and neurochemical identity of the excitatory neuronal input to the PBN remain largely unexplored. Here, we hypothesize that hindbrain glucagon-like peptide 1 (GLP-1) neurons provide excitatory inputs to the PBN, activation of which may lead to a reduction in feeding behavior.

Read the full article

Mind over platter: pre-meal planning and the control of meal size in humans

Brunstrom J.M. International Journal of Obesity (2014) 38, S9–S12

It is widely accepted that meal size is governed by psychological and physiological processes that generate fullness towards the end of a meal. However, observations of natural eating behaviour suggest that this preoccupation with within-meal events may be misplaced and that the role of immediate post-ingestive feedback (for example, gastric stretch) has been overstated. This review considers the proposition that the locus of control is more likely to be expressed in decisions about portion size, before a meal begins. Consistent with this idea, we have discovered that people are extremely adept at estimating the ‘expected satiety’ and ‘expected satiation’ of different foods. These expectations are learned over time and they are highly correlated with the number of calories that end up on our plate. Indeed, across a range of foods, the large variation in expected satiety/satiation may be a more important determinant of meal size than relatively subtle differences in palatability. Building on related advances, it would also appear that memory for portion size has an important role in generating satiety after a meal has been consumed. Together, these findings expose the importance of planning and episodic memory in the control of appetite and food intake in humans.

Read the full article

Page 3 of 4