States Of Satiety Research Articles

Hunger, Satiety, and Their Vulnerabilities.

The psychological states of hunger and satiety play an important role in regulating human food intake. Several lines of evidence suggest that these states rely upon declarative learning and memory processes, which are based primarily in the medial temporal lobes (MTL). The MTL, and particularly the hippocampus, is unusual in that it is especially vulnerable to insult. Consequently, we examine here the impact on hunger and satiety of conditions that: (1) are central to ingestive behaviour and where there is evidence of MTL pathology (i.e., habitual consumption of a Western-style diet, obesity, and anorexia nervosa); and (2) where there is overwhelming evidence of MTL pathology, but where ingestive behaviour is not thought central (i.e., temporal lobe epilepsy and post-traumatic stress disorder). While for some of these conditions the evidence base is currently limited, the general conclusion is that MTL impairment is linked, sometimes strongly, to dysfunctional hunger and satiety. This focus on the MTL, and declarative learning and memory processes, has implications for the development of alternative treatment approaches for the regulation of appetite.

AgRP neuron cis-regulatory analysis across hunger states reveals that IRF3 mediates leptin’s acute effects

AgRP neurons in the arcuate nucleus of the hypothalamus (ARC) coordinate homeostatic changes in appetite associated with fluctuations in food availability and leptin signaling. Identifying the relevant transcriptional regulatory pathways in these neurons has been a priority, yet such attempts have been stymied due to their low abundance and the rich cellular diversity of the ARC. Here we generated AgRP neuron-specific transcriptomic and chromatin accessibility profiles from male mice during three distinct hunger states of satiety, fasting-induced hunger, and leptin-induced hunger suppression. Cis-regulatory analysis of these integrated datasets enabled the identification of 18 putative hunger-promoting and 29 putative hunger-suppressing transcriptional regulators in AgRP neurons, 16 of which were predicted to be transcriptional effectors of leptin. Within our dataset, Interferon regulatory factor 3 (IRF3) emerged as a leading candidate mediator of leptin-induced hunger-suppression. Measures of IRF3 activation in vitro and in vivo reveal an increase in IRF3 nuclear occupancy following leptin administration. Finally, gain- and loss-of-function experiments in vivo confirm the role of IRF3 in mediating the acute satiety-evoking effects of leptin in AgRP neurons. Thus, our findings identify IRF3 as a key mediator of the acute hunger-suppressing effects of leptin in AgRP neurons.

The neuropeptide drosulfakinin enhances choosiness and protects males from the aging effects of social perception.

The motivation to reproduce is a potent natural drive, and the social behaviors that induce it can severely impact animal health and lifespan. Indeed, in Drosophila males, accelerated aging associated with reproduction arises not from the physical act of courtship or copulation but instead from the motivational drive to court and mate. To better understand the mechanisms underlying social effects on aging, we studied male choosiness for mates. We found that increased activity of insulin-producing cells (IPCs) of the fly brain potentiated choosiness without consistently affecting courtship activity. Surprisingly, this effect was not caused by insulins themselves, but instead by drosulfakinin (DSK), another neuropeptide produced in a subset of the IPCs, acting through one of the two DSK receptors, CCKLR-17D1. Activation of Dsk+ IPC neurons also decreased food consumption, while activation of Dsk+ neurons outside of IPCs affected neither choosiness nor feeding, suggesting an overlap between Dsk+neurons modulating choosiness and those influencing satiety. Broader activation of Dsk+ neurons (both within and outside of the IPCs) was required to rescue the detrimental effect of female pheromone exposure on male lifespan, as was the function of both DSK receptors. The same broad set of Dsk+ neurons was found to reinforce normally aversive feeding interactions, but only after exposure to female pheromones, suggesting that perception of the opposite sex gates rewarding properties of these neurons. We speculate that broad Dsk+ neuron activation is associated with states of satiety and social experience, which under stressful conditions is rewarding and beneficial for lifespan.

Implicit satiety goals and food-related expectations predict portion size in older adults: Findings from the BAMMBE cohort

Portion size selection is an indicator of appetite and within younger adults, is predicted by factors such as expected satiety, liking and motivations to achieve an ideal sensation of fullness (i.e., implicit satiety goals). Currently, there is limited research available on the determinants of portion size selection within older adults. Therefore, the current study aimed to examine the relationship between individual differences in implicit satiety goals, food-related expectations, and portion size selection in older adults. Free-living older adult Singaporeans (N = 115; Nmales = 62; age: M = 66.21 years, SD = 4.78, range = 60–83 years) participated as part of the Brain, Ageing, Microbiome, Muscle, Bone, and Exercise Study (BAMMBE). Participants completed questionnaires on their subjective requirements for experiencing different states of satiety and food-related expectations (i.e., liking, how filling) as well as a computerised portion size selection task. Using a multiple regression, we found that goals to feel comfortably full (B = 3.08, SE = 1.04, t = 2.96, p = .004) and to stop hunger (B = −2.25, SE = 0.82, t = −2.75, p = .007) significantly predicted larger portion size selection (R2 = 0.24, F(4,87) = 6.74, p < .001). Larger portion sizes (R2 = 0.53, F(5,90) = 20.58, p < .001) were also predicted by greater expected satiety (B = 0.47, SE = 0.09, t = 5.15, p < .001) and lower perceptions of how filling foods are (B = −2.92, SE = 0.77, t = −3.79, p < .001) but not liking (B = −0.09, SE = 0.91, t = −0.10, p = .925) or frequency (B = −18.42, SE = 16.91, t = −1.09, p = .279) of consumption of target foods. Comparing our findings to results of studies conducted with younger adults suggests the influence of factors such as satiety related goals on portion size selection may change with ageing while the influence of other factors (e.g., expected satiety/fullness delivered by foods) may remain consistent. These findings may inform future strategies to increase/decrease portion size accordingly to ensure older adults maintain an appropriate healthy weight.

Emotional eating and obesity in adults: the role of depression, sleep and genes.

Stress and other negative emotions, such as depression and anxiety, can lead to both decreased and increased food intake. The term 'emotional eating' has been widely used to refer to the latter response: a tendency to eat in response to negative emotions with the chosen foods being primarily energy-dense and palatable ones. Emotional eating can be caused by various mechanisms, such as using eating to cope with negative emotions or confusing internal states of hunger and satiety with physiological changes related to emotions. An increasing number of prospective studies have shown that emotional eating predicts subsequent weight gain in adults. This review discusses particularly three lines of research on emotional eating and obesity in adults. First, studies implying that emotional eating may be one behavioural mechanism linking depression and development of obesity. Secondly, studies highlighting the relevance of night sleep duration by showing that adults with a combination of shorter sleep and higher emotional eating may be especially vulnerable to weight gain. Thirdly, an emerging literature suggesting that genes may influence body weight partly through emotional eating and other eating behaviour dimensions. The review concludes by discussing what kind of implications these three avenues of research offer for obesity prevention and treatment interventions.

Blunted leptin sensitivity during hedonic overeating can be reinstated by activating galanin 2 receptors (Gal2R) in the lateral hypothalamus.

Since foods with high hedonic value are often consumed in excess of energetic needs, this study was designed to identify the mechanisms that may counter anorexigenic signalling in the presence of hedonic foods in lean animals. Mice, in different states of satiety (fed/fasted, or fed/fasted and treated with ghrelin or leptin, respectively), were allowed to choose between high-fat/high-sucrose and standard foods. Intake of each food type and the activity of hypothalamic neuropetidergic neurons that regulate appetite were monitored. In some cases, food choice was monitored in leptin-injected fasted mice that received microinjections of galanin receptor agonists into the lateral hypothalamus. Appetite-stimulating orexin neurons in the lateral hypothalamus are rapidly activated when lean, satiated mice consume a highly palatable food (PF); such activation (upregulated c-Fos expression) occurred even after administration of the anorexigenic hormone leptin and despite intact leptin signalling in the hypothalamus. The ability of leptin to restrain PF eating is restored when a galanin receptor 2 (Gal2R) agonist is injected into the lateral hypothalamus. Hedonically-loaded foods interrupt the inhibitory actions of leptin on orexin neurons and interfere with the homeostatic control of feeding. Overeating of palatable foods can be curtailed in lean animals by activating Gal2R in the lateral hypothalamus.

Avoiding hunger or attaining fullness? Implicit goals of satiety guide portion selection and food intake patterns

Although implicit theories have been studied in the context of personal traits, there has been limited investigation of their role in physiological domains such as appetite. Subjective feelings and affective states can function as goals and desired end states that individuals regulate their behaviors to attain. Likewise, different conceptualizations people maintain for the subjective experience of satiety (i.e., terminating hunger or attaining fullness) may also predict individual variations in eating behavior. We examined whether portion selection and food intake were guided by such implicit goals pertaining to the nature of satiety. Across 3 studies, we observed that individuals report distinct subjective requirements (degrees of fullness) to attain different states of satiety (stop hunger, feel comfortably full, feel completely full), suggesting that these states reflect independent goals or outcomes. Importantly, personal requirements to feel completely full (compared to stop hunger or feel comfortably full) were observed to be the strongest predictor of portion sizes selected in Study 1 (B = 1.17, p < .001) and Study 2 (B = 4.26, p = .004), and the quantity of energy consumed from a meal in Study 2 (B = 3.07, p = .01). Yet, experimentally activating a situational goal to stop hunger (vs. feel full) produced the selection of smaller portion sizes, F(1, 41) = 5.64, p = .02, and personal requirements to stop hunger to become the dominant predictor of portion selection patterns in Study 3 (B = 0.43, p = .005). These findings reveal that eating behaviors of modern consumers may be guided by a predominant goal to attain the subjective experience of complete fullness, although this implicit goal may be malleable to situational demands.

Cognitive Control of Eating: the Role of Memory in Appetite and Weight Gain

Purpose of reviewThe present review organises the recent literature on the role of memory in eating behaviours and provides an overview of the current evidence relating to the associations between memory and weight gain.Recent findingsResearch over the last few years has highlighted working memory as an important cognitive process that underpins many aspects of appetite control. Recent work on episodic memory and appetite has replicated work showing that manipulating memory for recent eating affects later consumption and extended this work to examine associations between individual differences in memory and eating behaviours. Poorer episodic memory ability is related to a reduced sensitivity to internal states of hunger and satiety and a tendency towards uncontrolled eating. There is also recent evidence to suggest that working memory and episodic memory impairments are related to weight gain and high BMI.SummaryWorking memory and episodic memory are core cognitive processes that are critical for food-related decision-making, and disruption to these processes contributes to problems with appetite control and weight gain, which suggests that weight loss programmes might be improved by the addition of cognitive training.

Hunger as a Context: Food Seeking That Is Inhibited During Hunger Can Renew in the Context of Satiety

At the end of a diet, even a successful one, people often return to overeating. One potential reason is that the behavioral inhibition that people learn while dieting might not readily transfer outside the context in which it is learned: Basic research indicates that after a behavior is inhibited, a return to the conditioning context or simple removal from the treatment context can cause the behavior to return (i.e., to renew). Can states of hunger and satiety play the role of context? In two experiments, rats learned a food-seeking response that earned sucrose or sweet, fatty food pellets while they were satiated. Responding was then inhibited (i.e., extinguished) while the rats were hungry. On the rats’ return to the satiated state, their food seeking was renewed. Additional results suggest that associations with hunger or satiety stimuli were learned more readily than associations with other potentially useful exteroceptive stimuli. The findings have implications for understanding the role of interoceptive contexts in controlling the inhibition of motivated behavior.

Children's expectations about training the approximate number system.

Humans possess a developmentally precocious and evolutionarily ancient approximate number system (ANS) whose sensitivity correlates with uniquely human symbolic arithmetic skills. Recent studies suggest that ANS training improves symbolic arithmetic, but such studies may engender performance expectations in their participants that in turn produce the improvement. Here, we assessed 6- to 8-year-old children's expectations about the effects of numerical and non-numerical magnitude training, as well as states of satiety and restfulness, in the context of a study linking children's ANS practice to their improved symbolic arithmetic. We found that children did not expect gains in symbolic arithmetic after exercising the ANS, although they did expect gains in ANS acuity after training on any magnitude task. Moreover, children expected gains in symbolic arithmetic after a good night's sleep and their favourite breakfast. Thus, children's improved symbolic arithmetic after ANS training cannot be explained by their expectations about that training.

Nutrition, energy intake- output, exercise, and fluid homeostasis during fasting in Ramadan

The month long ritual fasting undertaken by Muslims in Ramadan though intermittent in that they abstain from eating and drinking from dawn till dusk only, it is absolute during the span of fasting as they are forbidden from taking anything by mouth be it water, fruits or even oral medications. There are bound to be changes in their life style, sleep hours, physical activities, food consumption, meals frequencies, and dietary habits for different reasons. Proper management of food and fluid intake and exercise activity regulation is essential so that the spiritual fasting of Ramadan becomes an enjoyable experience free from avoidable hardships for all those who are found fit to undertake Ramadan fasting. Controlled studies are required to unravel the mysteries surrounding the complete understanding of the physiological states of satiety, hunger and fasting, and the role of both internal and external factors of orexigenic and anorexogenic nature and the scientific basis of the relative ease with which millions of Muslims the world over are able to observe the month-long Ramadan fast.

The Role of NPY and Ghrelin in Anorexia Nervosa

Complex mechanisms have evolved that control feeding and energy homeostasis in mammals. Centrally, particularly in the hypothalamus, numerous neurotransmitters have been identified that regulate appetite and energy homeostasis. On the other hand, hormones released from the gut signal states of hunger and satiety to the brain. From the large number of players involved in this interplay, peptides from the neuropeptide Y (NPY) family are unique, with the predominantly neuronally expressed NPY being one of the most strongly stimulating agents for food intake while its two other closely related family members peptide YY (PYY) and pancreatic polypeptide (PP) released from the gut induce satiety. Another major player in this circuitry is ghrelin, which is released from the stomach and is the only known hormone that signals hunger to the brain. It is doing this by stimulating hypothalamic NPY production and release, subsequently leading to increased appetite and feeding behaviour. Deregulation of these processes can lead to either the development of obesity or the other extreme, anorexia. The aim of this review is to summarize the recent literature on NPY and ghrelin and its involvement in anorexia nervosa.

Food motivation circuitry hypoactivation related to hedonic and nonhedonic aspects of hunger and satiety in women with active anorexia nervosa and weight-restored women with anorexia nervosa

Previous studies have provided evidence of food motivation circuitry dysfunction in individuals with anorexia nervosa. However, methodological limitations present challenges to the development of a cohesive neurobiological model of anorexia nervosa. Our goal was to investigate the neural circuitry of appetite dysregulation across states of hunger and satiety in active and weight-restored phases of anorexia nervosa using robust methodology to advance our understanding of potential neural circuitry abnormalities related to hedonic and nonhedonic state and trait. We scanned women with active anorexia nervosa, weight-restored women with anorexia nervosa and healthy-weight controls on a 3-T Siemens magnetic resonance scanner while they viewed images of high- and low-calorie foods and objects before (premeal) and after (postmeal) eating a 400 kcal meal. We enrolled 12 women with active disease, 10 weight-restored women with anorexia nervosa and 11 controls in our study. Compared with controls, both weight-restored women and those with active disease demonstrated hypoactivity premeal in the hypothalamus, amygdala and anterior insula in response to high-calorie foods (v. objects). Postmeal, hypoactivation in the anterior insula persisted in women with active disease. Percent signal change in the anterior insula was positively correlated with food stimuli ratings and hedonic and nonhedonic appetite ratings in controls, but not women with active disease. Our findings are limited by a relatively small sample size, which prevented the use of an analysis of variance model and exploration of interaction effects, although our substantial effect sizes of between-group differences suggest adequate power for our statistical analysis approach. Participants taking psychotropic medications were included. Our data provide evidence of potential state and trait hypoactivations in food motivation regions involved in the assessment of food's reward value and integration of these with interoceptive signalling of one's internal state of well-being, with important relations between brain activity and homeostatic and hedonic aspects of appetite. Our findings give novel evidence of disruption in neurobiological circuits and stress the importance of examining both state and trait characteristics in the investigation of brain phenotypes in individuals with anorexia nervosa.

Males and females show differential brain activation to taste when hungry and sated in gustatory and reward areas

Although males and females differ in eating behavior and prevalence rates for eating disorders and obesity, little is known about gender differences in cortical activation to pleasant and unpleasant pure tastes during the physiological states of hunger and satiety. Twenty-one healthy young adults (12 females and 9 males) underwent two functional magnetic resonance imaging scans. Using four pure tastants of differing qualities (i.e., salty, sour, bitter, sweet), the present study examined gender differences in fMRI activation during two motivational states (hunger and satiety). There was greater change in fMRI activation from hunger to satiety in males than females in response to all tastes within the middle frontal gyrus (BA 10), insula, and cerebellum. Males also had greater change in activation from hunger to satiety, relative to females, in limbic regions including dorsal striatum, amygdala, parahippocampal gyrus, and posterior and anterior cingulate; however, activation was stimulus dependent, despite equivalent ratings in perceived pleasantness and intensity. Interestingly, males and females showed significant change from hunger to satiety in response to citric acid, suggesting that in addition to gender and physiological condition, stimulus quality is an important factor in taste fMRI activation. These gender differences may have implications for the pathophysiology of eating disorders and obesity.

Recurrent, robust and scalable patterns underlie human approach and avoidance.

BackgroundApproach and avoidance behavior provide a means for assessing the rewarding or aversive value of stimuli, and can be quantified by a keypress procedure whereby subjects work to increase (approach), decrease (avoid), or do nothing about time of exposure to a rewarding/aversive stimulus. To investigate whether approach/avoidance behavior might be governed by quantitative principles that meet engineering criteria for lawfulness and that encode known features of reward/aversion function, we evaluated whether keypress responses toward pictures with potential motivational value produced any regular patterns, such as a trade-off between approach and avoidance, or recurrent lawful patterns as observed with prospect theory.Methodology/Principal FindingsThree sets of experiments employed this task with beautiful face images, a standardized set of affective photographs, and pictures of food during controlled states of hunger and satiety. An iterative modeling approach to data identified multiple law-like patterns, based on variables grounded in the individual. These patterns were consistent across stimulus types, robust to noise, describable by a simple power law, and scalable between individuals and groups. Patterns included: (i) a preference trade-off counterbalancing approach and avoidance, (ii) a value function linking preference intensity to uncertainty about preference, and (iii) a saturation function linking preference intensity to its standard deviation, thereby setting limits to both.Conclusions/SignificanceThese law-like patterns were compatible with critical features of prospect theory, the matching law, and alliesthesia. Furthermore, they appeared consistent with both mean-variance and expected utility approaches to the assessment of risk. Ordering of responses across categories of stimuli demonstrated three properties thought to be relevant for preference-based choice, suggesting these patterns might be grouped together as a relative preference theory. Since variables in these patterns have been associated with reward circuitry structure and function, they may provide a method for quantitative phenotyping of normative and pathological function (e.g., psychiatric illness).

Age-related functional changes in gustatory and reward processing regions: An fMRI study

Changes in appetite in older adults may result in unhealthy weight change and negatively affect overall nutrition. Research examining gustatory processing in young adults has linked changes in patterns of the hemodynamic response of gustatory and motivation related brain regions to the physiological states of hunger and satiety. Whether the same brain regions are involved in taste processing in older adults is unknown. The current study used functional magnetic resonance imaging (fMRI) to examine age-related changes in gustatory processing during hedonic assessment. Caffeine, citric acid, sucrose, and NaCl were administered orally during two event-related fMRI sessions, one during hunger and one after a pre-load. Participants assessed the pleasantness of the solutions in each session. Increased activity of the insula was seen in both age groups during hunger. Activity of secondary and higher order taste processing and reward regions such as the orbitofrontal cortex, amygdala, hippocampus, thalamus, and caudate nucleus was also observed. Hunger and satiety differentially affected the hemodynamic response, resulting in positive global activation during hunger and negative during satiety in both age groups. While in a state of hunger, the frequency and consistency of positive activation in gustatory and reward processing regions was greater in older adults. Additional regions not commonly associated with taste processing were also activated in older adults. Investigating the neurological response of older adults to taste stimuli under conditions of hunger and satiety may aid in understanding appetite, health, and functional changes in this population.

Eigenvector Centrality Mapping for Analyzing Connectivity Patterns in fMRI Data of the Human Brain

Functional magnetic resonance data acquired in a task-absent condition (“resting state”) require new data analysis techniques that do not depend on an activation model. In this work, we introduce an alternative assumption- and parameter-free method based on a particular form of node centrality called eigenvector centrality. Eigenvector centrality attributes a value to each voxel in the brain such that a voxel receives a large value if it is strongly correlated with many other nodes that are themselves central within the network. Google's PageRank algorithm is a variant of eigenvector centrality. Thus far, other centrality measures - in particular “betweenness centrality” - have been applied to fMRI data using a pre-selected set of nodes consisting of several hundred elements. Eigenvector centrality is computationally much more efficient than betweenness centrality and does not require thresholding of similarity values so that it can be applied to thousands of voxels in a region of interest covering the entire cerebrum which would have been infeasible using betweenness centrality. Eigenvector centrality can be used on a variety of different similarity metrics. Here, we present applications based on linear correlations and on spectral coherences between fMRI times series. This latter approach allows us to draw conclusions of connectivity patterns in different spectral bands. We apply this method to fMRI data in task-absent conditions where subjects were in states of hunger or satiety. We show that eigenvector centrality is modulated by the state that the subjects were in. Our analyses demonstrate that eigenvector centrality is a computationally efficient tool for capturing intrinsic neural architecture on a voxel-wise level.

FTO Regulates Reward-Based Decision Making and The Homeostatic Control Of Hunger And Satiety

Event Abstract Back to Event FTO Regulates Reward-Based Decision Making and The Homeostatic Control Of Hunger And Satiety Burkhard Pleger1, 2*, Annette Horstmann1, Jöran Lepsien3, Haiko Schloegl4, Stefan Kabisch4, Peter Kovacs5, Katja Macher6, Anke Tönjes4, Franziska Busse4, Michael Stumvoll4 and Arno Villringer1, 2 1 Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Germany 2 University of Leipzig, Clinic for Cognitive Neurology, Germany 3 Max Planck Institute for Human Cognitive and Brain Sciences, Nuclear Magnetic Resonance Unit, Germany 4 University of Leipzig, Department fo Medicine, Germany 5 University of Leipzig, Interdisciplinary Center of Clinical Research, Germany 6 Max Planck Institute for Human Cognitive and Brain Sciences, Department of Psychology, Germany Reward mechanisms governed by midbrain dopaminergic neurons and changes in eating control are implicated in the etiology of obesity. In humans, FTO polymorphism is the largest known monogenetic predictor for increased bodyweight. Here we report that two different FTO obesity risk alleles on the same chromosome (at rs8053740 and rs9939609) were associated with differences in phenotype. FTO rs8053740 alters reward-based decision making with enhanced reward-sensitivity to short term large gains and shortsightedness for infrequent but high punishments in the Iowa Gambling Task. In addition, voxel based morphometry (VBM) of structural MRI scans revealed that the FTO risk allele is associated with increased gray matter density in the right lateral orbitofrontal cortex (OFC), a structure involved in the regulation of reward-based decision making. Carriers of the FTO obesity risk allele rs9939609 showed no alterations in reward-based decision making. Using functional MRI, we however show an FTO rs9939609-dependent inability of the hypothalamus to differentially adapt to states of hunger and satiety. Collectively, we provide novel evidence for different FTO-dependent influences on reward-related behavior and homeostatic control of hunger and satiety. This suggests that the common FTO–dependent risk for obesity relies on multiple allele-specific genetic expressions and phenotypes. Keywords: decision-making, fMRI, FTO, Genetic polymorphisms, obesity risk alleles, Reward Conference: Decision Neuroscience From Neurons to Societies, Berlin, Germany, 23 Sep - 25 Sep, 2010. Presentation Type: Speaker Topic: Decision Making and Disorders Citation: Pleger B, Horstmann A, Lepsien J, Schloegl H, Kabisch S, Kovacs P, Macher K, Tönjes A, Busse F, Stumvoll M and Villringer A (2010). FTO Regulates Reward-Based Decision Making and The Homeostatic Control Of Hunger And Satiety. Front. Neurosci. Conference Abstract: Decision Neuroscience From Neurons to Societies. doi: 10.3389/conf.fnins.2010.82.00040 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 08 Sep 2010; Published Online: 10 Sep 2010. * Correspondence: Dr. Burkhard Pleger, Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany, burkhard.v.pleger@rub.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Burkhard Pleger Annette Horstmann Jöran Lepsien Haiko Schloegl Stefan Kabisch Peter Kovacs Katja Macher Anke Tönjes Franziska Busse Michael Stumvoll Arno Villringer Google Burkhard Pleger Annette Horstmann Jöran Lepsien Haiko Schloegl Stefan Kabisch Peter Kovacs Katja Macher Anke Tönjes Franziska Busse Michael Stumvoll Arno Villringer Google Scholar Burkhard Pleger Annette Horstmann Jöran Lepsien Haiko Schloegl Stefan Kabisch Peter Kovacs Katja Macher Anke Tönjes Franziska Busse Michael Stumvoll Arno Villringer PubMed Burkhard Pleger Annette Horstmann Jöran Lepsien Haiko Schloegl Stefan Kabisch Peter Kovacs Katja Macher Anke Tönjes Franziska Busse Michael Stumvoll Arno Villringer Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A Neural Circuit Mechanism Integrating Motivational State with Memory Expression in Drosophila

Behavioral expression of food-associated memory in fruit flies is constrained by satiety and promoted by hunger, suggesting an influence of motivational state. Here, we identify a neural mechanism that integrates the internal state of hunger and appetitive memory. We show that stimulation of neurons that express neuropeptide F (dNPF), an ortholog of mammalian NPY, mimics food deprivation and promotes memory performance in satiated flies. Robust appetitive memory performance requires the dNPF receptor in six dopaminergic neurons that innervate a distinct region of the mushroom bodies. Blocking these dopaminergic neurons releases memory performance in satiated flies, whereas stimulation suppresses memory performance in hungry flies. Therefore, dNPF and dopamine provide a motivational switch in the mushroom body that controls the output of appetitive memory.

Cortical activation in response to pure taste stimuli during the physiological states of hunger and satiety

This event-related functional magnetic resonance imaging (er-fMRI) study investigated BOLD signal change in response to a series of pure gustatory stimuli that varied in stimulus quality when subjects were hungry and sated with a nutritional pre-load. Group analyses showed significant differences in activation in the hunger minus satiety condition in response to sucrose, caffeine, saccharin, and citric acid within the thalamus, hippocampus, and parahippocampus. When examining the hunger and satiety conditions, activation varied as a function of stimulus, with the majority of the stimuli exhibiting significantly greater activation in the hunger state within the insula, thalamus, and substantia nigra, in contrast to decreased activation in the satiated state within the parahippocampus, hippocampus, amygdala, and anterior cingulate. Region of interest (ROI) analysis revealed two significant interactions, ROI by physiology and ROI by physiology by stimulus. In the satiety condition, the primary (inferior and superior insulae) and secondary (OFC 11 and OFC 47) taste regions exhibited significantly greater brain activation in response to all stimuli than regions involved in processing eating behavior (hypothalamus), affect (amygdala), and memory (hippocampus, parahippocampus and entorhinal cortex). These same regions demonstrated significantly greater activation within the hunger condition than the satiety condition, with the exception of the superior insula. Furthermore, the patterns of activation differed as a function taste stimulus, with greater activation in response to sucrose than to the other stimuli. These differential patterns of activation suggest that the physiological states of hunger and satiety produce divergent activation in multiple brain areas in response to different pure gustatory stimuli.