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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.

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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.

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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.

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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.

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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.

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You are what you eat: a neuroscience perspective on consumers’ personality characteristics as determinants of eating behavior

 

Van der Laan, L.N., Smeets, P.A.M. Current Opinion in Food Science 2015 Vol 3: 11-18

Evidence for a link between personality characteristics and eating behavior is mounting. However, the underlying neurobiological mechanisms remain unclear. In this review and meta-analysis we summarize the current knowledge on personality characteristics in relation to food-induced brain responses and suggest topics for future research. Overall, the number of studies is low and there is significant variability in findings: the variability in findings related to single personality characteristics was of similar magnitude as that between different personality characteristics. Nevertheless, many food-specific personality characteristics are interrelated and modulate food-induced brain responses in similar brain areas as more general personality characteristics do. To advance the field and improve consumer profiling, standardized measures of food-related brain responses and personality characteristics are required.

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Gut instinct: body weight homeostasis in health and obesity.

Gareth Leng. Exp Physiol. 2014 Sep 1;99(9):1101-3.

Prof Gareth Leng (University of Edinburgh) recently published an article outlining current controversies and approaches in obesity research. This commentary introduces a special issue of Experimental Physiology marking the Physiological Society’s recent scientific meeting on obesity that featured work from Nudge-it scientists.       read the full article

 

 

 

Magnetoencephalographic Signatures of Right Prefrontal Cortex Involvement in Response Inhibition

Maike A. Hege, Hubert Preissl and Krunoslav T. Stingl.   Human Brain Mapping  Vol 35:Issue 9

Prevention and reversion of weight gain requires strong control of food intake. Particularly important in inhibiting the impulse to consume additional, unnecessary calories might be the cognitive control process of response inhibition as it allows us to inhibit actions, thoughts, and impulses that are inappropriate in a given context. Response inhibition of motor actions can be investigated in go-nogo tasks, in which subjects are required to perform speeded responses on go trials and to withhold responses on nogo trials. In our study, the role of prefrontal brain networks during response inhibition to food and toy pictures was investigated. In particular, we used magnetoencephalography to explore the temporal dynamics and neurophysiological nature of the activity in right dorsolateral prefrontal cortex (rDLPFC). It was shown that rDLPFC showed increased activity during response inhibition and that the temporal dynamics of this activity supported a role of rDLPFC in guiding the selection of inhibiting the response. Further results suggested that right prefrontal alpha band activity might be involved in this gating. With regard to the control of food intake, this prefrontal activity might be essential when selecting not to eat more or certain kinds of high caloric palatable food. In an additional study we already observed reduced activity in prefrontal brain areas during response inhibition to food pictures for obese subjects with binge eating disorder in comparison to obese subjects without binge eating disorder (Hege et al. 2014, Int J Obes). This observation might explain the inability of binge eating disorder patients to control their temporary excessive food intake.   read the full article