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Tastes change over time. People’s tastes are distorted through two channels: satiation formation and habit formation. In this paper, we develop a theoretical foundation of satiation and habituation by an axiomatic approach. Our theory is based on a hierarchy of preference conditions called compensation independence. The behavioral assumption underlying the preference conditions are the psychological compensation of human beings. I flesh out an axiomatic system for general models of satiation and habit formation, which contains many functional forms in the literature as special cases. Moreover, I advance the axiomatization to accommodate the linear representations of satiation and habit formation that are prevailing in the literature. This paper contributes to the birth of a new generation of the behavioral foundation for modeling satiation and habit formation, which might improve on the current state of the art in understanding people’s tastes over time and preferences. Theoretically, this study contributes to the vein of time-nonseparable preferences.

Objective: Obesity is characterized by dysregulated homeostatic mechanisms resulting in positive energy balance; however, when this dysregulation occurs is unknown. We assessed the time course of alterations to behaviors promoting weight gain in male and female mice switched to an obesogenic high-fat diet (HFD)., Methods: Male and female C57BL/6J mice were housed in metabolic chambers and were switched from chow to a 60% or 45% HFD for 4 and 3 weeks, respectively. Food intake, meal patterns, energy expenditure (EE), and body weight were continuously measured. A separate cohort of male mice was switched from chow to a 60% HFD and was given access to locked or unlocked running wheels., Results: Switching mice to obesogenic diets promotes transient bouts of hyperphagia during the first 2 weeks followed by persistent caloric hyperphagia. EE increases but not sufficiently enough to offset increased caloric intake, resulting in a sustained net positive energy balance. Hyperphagia is associated with consumption of calorically larger meals (impaired satiation) more frequently (impaired satiety), particularly during the light cycle. Running wheel exercise delays weight gain in male mice fed a 60% HFD by enhancing satiation and increasing EE. However, exercise effects on satiation are no longer apparent after 2 weeks, coinciding with weight gain., Conclusions: Exposure to obesogenic diets engages homeostatic regulatory mechanisms for ~2 weeks that ultimately fail, and consequent weight gain is characterized by impaired satiation and satiety. Insights into the etiology of obesity can be obtained by investigating changes to satiation and satiety mechanisms during the initial ~2 weeks of HFD exposure., (© 2024 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.)

Training interoceptive sensitivity (IS) might be a first step in effectively promoting intuitive eating (IE). A dyadic interoception-based pilot randomized controlled trial was conducted to increase IE among couples aged 50+. The training consisted of three exercises, a Body Scan (BS), a hunger exercise (HU), and a satiety (SA) exercise. This study explored how spouses accepted the (dyadic vs. single) training. In a mixed-methods convergence design, the findings of a survey ( n = 68 couples) and focus groups ( n = 4) were synthesized. Moderate general acceptance (e.g., regarding feasibility and low burden) and a hierarchical gradient in favor of the BS (e.g., pleasantness and improved sleep quality) emerged. Barriers concerned a perceived lack of the exercises' usefulness and a limited understanding of the training purpose. A wish for regular feedback and exchange with the study stuff and other participants was expressed. Spousal training involvement was experienced as being rather beneficial. Previously harmonized dietary practices and daily routines appeared as constructive pre-conditions for the joint training. This study highlights the potential and implications of training couples in IS. Future interventions should involve a regular exchange and closer guidance by study staff to promote a better understanding of the processes and goals of IS and IE.

Background: Insulin exerts a crucial impact on glucose control, cellular growing, function, and metabolism. It is partially modulated by nutrients, especially as a response to the intake of foods, including carbohydrates. Moreover, insulin can exert an anorexigenic effect when inserted into the hypothalamus of the brain, in which a complex network of an appetite/hunger control system occurs. The current literature review aims at thoroughly summarizing and scrutinizing whether insulin release in response to glucose exposure may be a better choice to control body weight gain and related diseases compared to the use of sucrose substitutes (SSs) in combination with a long-term, well-balanced diet., Methods: This is a comprehensive literature review, which was performed through searching in-depth for the most accurate scientific databases and applying effective and relevant keywords., Results: The insulin action can be inserted into the hypothalamic orexigenic/anorexigenic complex system, activating several anorexigenic peptides, increasing the hedonic aspect of food intake, and effectively controlling the human body weight. In contrast, SSs appear not to affect the orexigenic/anorexigenic complex system, resulting in more cases of uncontrolled body weight maintenance while also increasing the risk of developing related diseases., Conclusions: Most evidence, mainly derived from in vitro and in vivo animal studies, has reinforced the insulin anorexigenic action in the hypothalamus of the brain. Simultaneously, most available clinical studies showed that SSs during a well-balanced diet either maintain or even increase body weight, which may indirectly be ascribed to the fact that they cannot cover the hedonic aspect of food intake. However, there is a strong demand for long-term longitudinal surveys to effectively specify the impact of SSs on human metabolic health.

Initial evidence suggests that body appreciation prospectively predicts intuitive eating. However, the limited number of longitudinal studies focused solely on girls and women, with a lack of evaluation among men. Furthermore, the underlying mechanisms explaining this relationship remain poorly understood. The present study examined whether body appreciation prospectively predicted intuitive eating facets among women and men in Germany. We also tested whether adaptive affect regulation skills (i.e., body image flexibility) mediated these relationships. We analyzed data from 1436 women and 704 men across three time points: Baseline (T1), 6-month (T2), and 12-month (T3) follow-up, using latent variable path models to assess direct and indirect effects. Among women, T1 body appreciation directly predicted T3 body-food choice congruence. Additionally, body appreciation indirectly predicted unconditional permission to eat, eating for physical rather than emotional reasons, and reliance on hunger and satiety cues at T3 via its effect on T2 body image flexibility. Among men, T1 body appreciation indirectly predicted T3 eating for physical rather than emotional reasons via T2 body image flexibility. Our findings suggest that body image flexibility plays a pivotal role in explaining why individuals who appreciate their bodies are more likely to eat intuitively., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Repeated consumption of products and experiences leads to a reduction in enjoyment over time, a phenomenon that is commonly referred to as "satiation." Three studies show that consumers satiate more slowly to products that are consistent with a currently active identity. Because satiation is a natural human response when consuming a product repeatedly, all consumers are likely to feel the pull downward on their product enjoyment over time. This drop in enjoyment produces dissonance in consumers with an activated identity because reduced enjoyment with identity-consistent products conflicts with their identity. Resisting this drop results in lowered levels of satiation, and these satiation differences are even reflected in subsequent consumption behavior. These results have theoretical implications both for the nascent research area of satiation in consumer behavior and for developing a fuller sense of the relationship between consumer identity and consumption. [ABSTRACT FROM AUTHOR]

Satiation of need is generally ignored by growth theory. I study a model where consumers may be satiated in any given good but new goods may be introduced. A social planner will never elect a trajectory with long-run satiation. Instead, he will introduce enough new goods to avoid such a situation. In contrast, the decentralized equilibrium may involve long run satiation. This, despite that the social costs of innovation are second order compared to their social benefits. Multiple equilibria may arise: depending on expectations, the economy may then converge to a satiated steady state or a non satiated one. In the latter equilibrium, capital and the number of varieties are larger than in the former, while consumption of each good is lower. This multiplicity comes from the following strategic complementarity: when people expect more varieties to be introduced in the future, this raises their marginal utility of future consumption, inducing them to save more. In turn, higher savings reduces interest rates, which boosts the rate of innovation. When TFP grows exogenously and labor supply is endogenized, the satiated equilibrium generically survives. For some parametrer values, its growth rate is positive while labor supply declines over time to zero. Its growth rate is then lower than that of the non satiated equilibrium. Hence, the economy may either coordinate on a high leisure, low growth, satiated "leisure society" or a low leisure, high growth, non satiated "consumption society". [ABSTRACT FROM AUTHOR]

The gastrointestinal tract plays a critical role in the regulation of energy homeostasis by initiating neural and hormonal responses to the ingestion of nutrients. In addition to peptide hormones, such as cholecystokinin (CKK) and peptide YY (PYY), the lipid-derived mediator oleoylethanolamide (OEA) has been implicated in the control of satiety. Previous studies in humans and rodent models have shown that obesity is associated with changes in CCK, PYY and other gut-derived peptide hormones, which may contribute to decreased satiety and increased energy intake. In the present study, we show that small-intestinal OEA production is disrupted in the gut of diet-induced obese (DIO) rats and mice. In lean rodents, feeding or duodenal infusion of Intralipid® or pure oleic acid stimulates jejunal OEA mobilization. This response is strikingly absent in DIO rats and mice. Confirming previous reports, we found that feeding rats or mice a high-fat diet for 7 days is sufficient to suppress jejunal OEA mobilization. Surprisingly, a similar effect is elicited by feeding rats and mice a high-sucrose low-fat diet for 7 days. Collectively, our findings suggest that high fat-induced obesity is accompanied by alterations in the post-digestive machinery responsible for OEA biosynthesis, which may contribute to reduced satiety and hyperphagia.

Somatostatin was discovered four decades ago as hypothalamic factor inhibiting growth hormone release. Subsequently, somatostatin was found to be widely distributed throughout the brain and to exert pleiotropic actions via interaction with five somatostatin receptors (sst1-5) that are also widely expressed throughout the brain. Interestingly, in contrast to the predominantly inhibitory actions of peripheral somatostatin, the activation of brain sst2 signaling by intracerebroventricular injection of stable somatostatin agonists potently stimulates food intake and independently, drinking behavior in rodents. The orexigenic response involves downstream orexin-1, neuropeptide Y1 and μ receptor signaling while the dipsogenic effect is mediated through the activation of the brain angiotensin 1 receptor. Brain sst2 activation is part of mechanisms underlying the stimulation of feeding and more prominently water intake in the dark phase and is able to counteract the anorexic response to visceral stressors.

Emerging evidence has suggested a possible physiologic role for peripheral glucagon-like peptide 1 (GLP-1) in regulating glucose metabolism and food intake. The likely site of action of GLP-1 is on vagal afferent neurons (VANs). The vagal afferent pathway is the major neural pathway by which information about ingested nutrients reaches the central nervous system and influences feeding behavior. Peripheral GLP-1 acts on VANs to inhibit food intake. The mechanism of the GLP-1 receptor (GLP-1R) is unlike other gut-derived receptors; GLP-1Rs change their cellular localization according to feeding status rather than their protein concentrations. It is possible that several gut peptides are involved in mediating GLP-1R translocation. The mechanism of peripheral GLP-1R translocation still needs to be elucidated. We review data supporting the role of peripheral GLP-1 acting on VANs in influencing glucose homeostasis and feeding behavior. We highlight evidence demonstrating that GLP-1 interacts with ghrelin and leptin to induce satiation. Our aim was to understand the mechanism of peripheral GLP-1 in the development of noninvasive antiobesity treatments.

ObjectiveThere is evidence of altered neural taste response in female adolescents who are obese (OB), and in adolescents who are at risk for obesity. To further understand risk factors for the development of overeating and obesity, we investigated response to tastes of sucrose and water in 23 OB and healthy weight (HW) children.Methods and designThirteen HW and 10 OB 8-12-year-old children underwent functional magnetic resonance imaging while tasting sucrose and water. Additionally, children completed an eating in the absence of hunger paradigm and a sucrose-liking task.ResultsA region of interest analysis revealed an elevated BOLD response to taste (sucrose and water) within the bilateral insula and amygdala in OB children relative to HW children. Whole-brain analyses revealed a group by condition interaction within the paracingulate, medial frontal, middle frontal gyri and right amygdala: post hoc analyses suggested an increased response to sucrose for OB relative to HW children, whereas HW children responded more strongly to water relative to sucrose. In addition, OB children, relative to HW, tended to recruit the right putamen as well as medial and lateral frontal and temporal regions bilaterally.ConclusionThis study showed increased reactivity in the amygdala and insula in the OB compared with HW children, but no functional differentiation in the striatum, despite differences in the striatum previously seen in older samples. These findings support the concept of the association between increased neural processing of food reward in the development of obesity, and raise the possibility that emotional and interoceptive sensitivity could be an early vulnerability in obesity.

Fat is a vital macronutrient, and its intake is closely monitored by an array of molecular sensors distributed throughout the alimentary canal. In the mouth, dietary fat constituents such as mono- and diunsaturated fatty acids give rise to taste signals that stimulate food intake, in part by enhancing the production of lipid-derived endocannabinoid messengers in the gut. As fat-containing chyme enters the small intestine, it causes the formation of anorexic lipid mediators, such as oleoylethanolamide, which promote satiety. These anatomically and functionally distinct responses may contribute to the homeostatic control and, possibly, the pathological dysregulation of food intake.

Bacterially derived factors are implicated in the causation and persistence of obesity. Ingestion of a high fat diet in rodents and obesity in human subjects is associated with chronic elevation of low plasma levels of lipopolysaccharide (LPS), a breakdown product of Gram-negative bacteria. The terminals of vagal afferent neurons are positioned within the gut mucosa to convey information from the gut to the brain to regulate food intake and are responsive to LPS. We hypothesized that chronic elevation of LPS could alter vagal afferent signaling. We surgically implanted osmotic mini-pumps that delivered a constant, low-dose of LPS into the intraperitoneal cavity of rats (12.5 μg/kg/hr for 6 weeks). LPS-treated rats developed hyperphagia and showed marked changes in vagal afferent neuron function. Chronic LPS treatment reduced vagal afferent leptin signaling, characterized by a decrease in leptin-induced STAT3 phosphorylation. In addition, LPS treatment decreased cholecystokinin-induced satiety. There was no alteration in leptin signaling in the hypothalamus. These findings offer a mechanism by which a change in gut microflora can promote hyperphagia, possibly leading to obesity.

Abdominal surgery inhibits food intake and induces c-Fos expression in the hypothalamic and medullary nuclei in rats. Rikkunshito (RKT), a Kampo medicine improves anorexia. We assessed the alterations in meal microstructure and c-Fos expression in brain nuclei induced by abdominal surgery and the modulation by RKT in mice. RKT or vehicle was gavaged daily for 1 week. On day 8 mice had no access to food for 6-7 h and were treated twice with RKT or vehicle. Abdominal surgery (laparotomy-cecum palpation) was performed 1-2 h before the dark phase. The food intake and meal structures were monitored using an automated monitoring system for mice. Brain sections were processed for c-Fos immunoreactivity (ir) 2-h after abdominal surgery. Abdominal surgery significantly reduced bouts, meal frequency, size and duration, and time spent on meals, and increased inter-meal interval and satiety ratio resulting in 92-86% suppression of food intake at 2-24 h post-surgery compared with control group (no surgery). RKT significantly increased bouts, meal duration and the cumulative 12-h food intake by 11%. Abdominal surgery increased c-Fos in the prelimbic, cingulate and insular cortexes, and autonomic nuclei, such as the bed nucleus of the stria terminalis, central amygdala, hypothalamic supraoptic (SON), paraventricular and arcuate nuclei, Edinger-Westphal nucleus (E-W), lateral periaqueduct gray (PAG), lateral parabrachial nucleus, locus coeruleus, ventrolateral medulla and nucleus tractus solitarius (NTS). RKT induced a small increase in c-Fos-ir neurons in the SON and E-W of control mice, and in mice with surgery there was an increase in the lateral PAG and a decrease in the NTS. These findings indicate that abdominal surgery inhibits food intake by increasing both satiation (meal duration) and satiety (meal interval) and activates brain circuits involved in pain, feeding behavior and stress that may underlie the alterations of meal pattern and food intake inhibition. RKT improves food consumption post-surgically that may involve modulation of pain pathway.

Remarkable advances have been made in recent years in our understanding of innate behavior and the underlying neural circuits. In particular, a wealth of neuromodulatory mechanisms have been uncovered that can alter the input-output relationship of a hereditary neural circuit. It is now clear that this inbuilt flexibility allows animals to modify their behavioral responses according to environmental cues, metabolic demands and physiological states. Here, we discuss recent insights into how modulation of neural circuits impacts innate behavior, with a special focus on how environmental cues and internal physiological states shape different aspects of feeding behavior in Drosophila.

As the northern Largemouth bass (LMB) (Micropterus nigricans) industry shifts toward fingerling production, implementing practical feeding strategies to ensure efficient growth during high water temperatures is paramount. Twenty (12.7 ± 0.2 g) (Trial 1) and fifteen (7.2 ± 0.1 g) (Trial 2) LMB fingerlings were stocked in two recirculating systems (each containing nine tanks), acclimated to 30 °C, with one system fed daily rations of 3, 5 and 7% body weight (Trial 1), and the second system fed to satiation daily, every second day, or every third day (Trial 2), for 28 days each. All treatments were triplicated. Multiple growth metrics and lipid composition were analyzed. The 3% treatment yielded the lowest final average weight (36.05 g) and FCR (0.83), with no difference in final biomass in Trial 1 treatments. Fish fed to satiation daily and every second day produced FCRs and biomasses of 0.83 and 356.78 g, and 0.93 and 272.26 g, respectively. There were no differences in total lipid concentration, however, fatty acid profiles differed significantly between all treatments within their respective trials. Feeding LMB fingerlings 3% of total body weight or feeding daily to satiation allows for efficient growth at 30 °C and implements cost-effective feeding strategies.

Adjunct clauses are traditionally assumed to be strong islands for extraction across languages. However, the universal island status of adjunct clauses has been challenged by studies showing that extraction is possible from finite adjunct clauses in the Mainland Scandinavian languages. The possibility of extraction in these languages appears to be affected by various factors, including the type of adjunct clause, the type of extraction dependency, and the presence of contextual facilitation. These findings call for a re-evaluation of the islandhood of adjunct clauses in English. We conducted an acceptability judgment study on relativization from three types of finite adjunct clauses in English (if-, when-, and because-clauses) in the presence of supporting context. We found that the three clause types showed rather non-uniform acceptability patterns: extraction from when- and because-clauses both yielded significantly lower ratings than extraction from if-clauses, which patterned with non-island that-clauses. Our results suggest that at least for relativization, if- and when-adjuncts are not invariably strong islands in English, and that extra-grammatical factors may be key in understanding island structures traditionally assumed to be purely syntactic in nature.

This paper provides an overview of categorical and gradient effects in islands, with a focus on English, and argues that most islands are gradient. In some cases, the island is circumvented by the construction type in which the extraction takes place, and there is growing evidence that the critical factor is pragmatic in nature, contrary to classic and categorical accounts of island effects that are favored in generative circles to this day. In other cases, the island effect is malleable and can weaken with increased exposure to the extraction pattern, a phenomenon traditionally referred to as ‘syntactic satiation’. However, it is not clear what satiation consists of. Some argue that it is nothing more than task adaptation (mere increased familiarity with the experimental paradigm, impacting difficult sentences more than easy ones), whereas others propose that it consists of a form of error-driven structure-dependent form of learning. The present paper discusses this controversy, and the broader adaptation debate, and argues that both task adaptation and grammatical adaptation are taking place during the processing of complex sentences, and that both frequency and attention are plausible factors to stimulate adaptation.

Summary: This systematic review with meta‐analyses aimed to identify the sensory and physical characteristics of foods/beverages which increase satiation and/or decrease/delay subsequent consumption without affecting acceptability. Systematic searches were first undertaken to identify review articles investigating the effects of any sensory and physical food characteristic on food intake. These articles provided some evidence that various textural parameters (aeration, hardness, homogeneity, viscosity, physical form, added water) can impact food intake. Individual studies investigating these effects while also investigating acceptability were then assessed. Thirty‐seven individual studies investigated a textural manipulation and provided results on food intake and acceptability, 13 studies (27 comparisons, 898 participants) investigated effects on satiation, and 29 studies (54 comparisons, 916 participants) investigated effects on subsequent intake. Meta‐analyses of within‐subjects comparisons (random‐effects models) demonstrated greater satiation (less weight consumed) from food products that were harder, chunkier, more viscous, voluminous, and/or solid, while demonstrating no effects on acceptability. Textural parameters had limited effects on subsequent consumption. Between‐subjects studies and sensitivity analyses confirmed these results. These findings provide some evidence that textural parameters can increase satiation without affecting acceptability. The development of harder, chunkier, more viscous, voluminous, and/or solid food/beverage products may be of value in reducing overconsumption. [ABSTRACT FROM AUTHOR]

Cocaine- and amphetamine-regulated transcript encodes an eponymous peptide, CARTp, which exerts diverse pharmacologic actions in the central and peripheral nervous systems, as well as in several endocrine organs, including pancreas. Here we review those diverse actions, the physiological relevance of which had remained unestablished until recently. With the identification of a CARTp receptor, GPR160, the physiologic importance and therapeutic potential of CARTp or analogs are being revealed. Not only is the CARTp-GPR160 interaction essential for the circadian regulation of appetite and thirst but also for the transmission of nerve injury-induced pain. Molecular approaches now are uncovering additional physiologically relevant actions and the development of acute tissue-specific gene compromise approaches may reveal even more physiologically relevant actions of this pluripotent ligand/receptor pair. [ABSTRACT FROM AUTHOR]

Satiation is influenced by a variety of signals including gastric distention and oro‐sensory stimulation. Here we developed a high‐field (9.4 T) functional magnetic resonance imaging (fMRI) protocol to test how oro‐sensory stimulation and gastric distention, as induced with a block‐design paradigm, affect brain activation under different states of energy balance in rats. Repeated tasting of sucrose induced positive and negative fMRI responses in the ventral tegmental area and septum, respectively, and gradual neural activation in the anterior insula and the brain stem nucleus of the solitary tract (NTS), as revealed using a two‐level generalized linear model‐based analysis. These unique findings align with comparable human experiments, and are now for the first time identified in rats, thereby allowing for comparison between species. Gastric distention induced more extensive brain activation, involving the insular cortex and NTS. Our findings are largely in line with human studies that have shown that the NTS is involved in processing both visceral information and taste, and anterior insula in processing sweet taste oro‐sensory signals. Gastric distention and sucrose tasting induced responses in mesolimbic areas, to our knowledge not previously detected in humans, which may reflect the rewarding effects of a full stomach and sweet taste, thereby giving more insight into the processing of sensory signals leading to satiation. The similarities of these data to human neuroimaging data demonstrate the translational value of the approach and offer a new avenue to deepen our understanding of the process of satiation in healthy people and those with eating disorders. [ABSTRACT FROM AUTHOR]

Legumes are an important source of plant-based protein that are known to provide many beneficial health effects, but their global consumption is low. Thus, processing legumes to improve their protein digestibility and incorporating them into commonly consumed foods could be a useful strategy to increase legume consumption and obtain the nutritional benefits, including increased protein intake and enhanced satiety. This review highlights various food processing techniques that can be utilised to enhance the digestibility of legume protein, particularly when used to enrich food products. Whether such a strategy benefits metabolic health, satiety perception, and postprandial hormone responses to such foods is then evaluated. Finally, consumer acceptance of legume-based food products is examined. Food processing techniques can be used to enhance the digestibility of legume protein, and this effect is evident when incorporating legume proteins into food products. The increased levels of protein in such foods are found to be more satiating by consumers, while also eliciting improved postprandial hormone responses, suggesting they would aid in improving metabolic health. The incorporation of legumes into foods may reduce the consumer acceptance of such products. However, by utilizing a combination of food processing techniques, the sensory properties of legumes can be effectively manipulated to improve the acceptability of legume-enriched food products. Thus, the incorporation of legume protein into foods appears to be a viable strategy to encourage legume consumption and improve overall health. [Display omitted] • Food processing enhances the protein digestibility of legume-enriched foods. • The incorporation of legumes into foods enhances satiation and satiety. • A balance between glycaemic responses and protein digestibility must be considered. • Food processing can improve the consumer acceptability of legume-enriched foods. [ABSTRACT FROM AUTHOR]

• Estradiol reduced water intake in response to 24 and 48 h water deprivation. • Estradiol reduced water intake through changes in drinking burst number. • Activation of estrogen receptor alpha reduced licks for water. • Estradiol produced a leftward shift in the dose-response curve of exendin-4. It is well documented that estrogens inhibit fluid intake. Most of this research, however, has focused on fluid intake in response to dipsogenic hormone and/or drug treatments in euhydrated rats. Additional research is needed to fully characterize the fluid intake effects of estradiol in response to true hypovolemia. As such, the goals of this series of experiments were to provide a detailed analysis of water intake in response to water deprivation in ovariectomized female rats treated with estradiol. In addition, these experiments also tested if activation of estrogen receptor alpha is sufficient to reduce water intake stimulated by water deprivation and tested for a role of glucagon like peptide-1 in the estrogenic control of water intake. As expected, estradiol reduced water intake in response to 24 and 48 h of water deprivation. The reduction in water intake was associated with a reduction in drinking burst number, with no change in drinking burst size. Pharmacological activation of estrogen receptor alpha reduced intake. Finally, estradiol-treatment caused a leftward shift in the behavioral dose response curve of exendin-4, the glucagon like peptide-1 agonist. While the highest dose of exendin-4 reduced 10 min intake in both oil and estradiol-treated rats, the intermediate dose only reduced intake in rats treated with estradiol. Together, this series of experiments extends previous research by providing a more thorough behavioral analysis of the anti-dipsogenic effect of estradiol in dehydrated rats, in addition to identifying the glucagon like peptide-1 system as a potential bioregulator involved in the underlying mechanisms by which estradiol reduces water intake in the female rat. [ABSTRACT FROM AUTHOR]

Little is known about how plant-based products influence satiation compared to corresponding meat-based products. As augmented reality (AR) intensifies sensory experiences, it was hypothesized to improve satiation. This study compared satiation between intake of meatballs and plant-based balls and plant-based balls intensified with AR for visual, olfactory, and haptic sensory properties. Intake order of the meatballs, plant-based balls, and augmented plant-based balls, eaten on separate days, was randomized. Satiation was measured from twenty-eight non-obese adults as ad libitum intake of the balls and extra snacks, and as subjective appetite sensations. Liking and wanting to eat the products were also investigated. There were no differences between the products in satiation. Before tasting the augmented plant-based balls were less liked than the meatballs (p = 0.002) or plant-based balls (p = 0.046), but after eating the first ball or eating the ad libitum number of balls the differences in liking disappeared. Wanting evaluations were similar for each product and decreased during eating (p < 0.001). A group of participants susceptible to AR was found (n = 11), described by decreased intake when augmentation was applied. Among the sub-group, wanting to eat the augmented balls was lower before tasting (p = 0.019) and after eating the first ball (p = 0.002) and appetite was less suppressed after eating the balls ad libitum (p = 0.01), when compared to non-susceptible participants. We conclude that meatballs and plant-based balls were equal in inducing satiation, and multisensory augmentation did not influence satiation. However, the augmentation decreased liking evaluations before tasting. Further studies are needed to explore differences between consumer groups in susceptibility to augmentation. [Display omitted] [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify overeating phenotypes and their correlates in overweight and obese children. One hundred and seventeen treatment-seeking overweight and obese 8-12year-old children and their parents completed the study. Children completed an eating in the absence of hunger (EAH) paradigm, the Eating Disorder Examination interview, and measurements of height and weight. Parents and children completed questionnaires that evaluated satiety responsiveness, food responsiveness, negative affect eating, external eating and eating in the absence of hunger. Latent profile analysis was used to identify heterogeneity in overeating phenotypes in the child participants. Latent classes were then compared on measures of demographics, obesity status and nutritional intake. Three latent classes of overweight and obese children were identified: High Satiety Responsive, High Food Responsive, and Moderate Satiety and Food Responsive. Results indicated that the High Food Responsive group had higher BMI and BMI-Z scores compared to the High Satiety Responsive group. No differences were found among classes in demographics or nutritional intake. This study identified three overeating phenotypes, supporting the heterogeneity of eating patterns associated with overweight and obesity in treatment-seeking children. These finding suggest that these phenotypes can potentially be used to identify high risk groups, inform prevention and intervention targets, and develop specific treatments for these behavioral phenotypes.

Background & aimsThe study of intrinsic fluctuations in the blood oxygen level-dependent signal of functional magnetic resonance imaging can provide insight into the effect of physiologic states on brain processes. In an effort to better understand the brain-gut communication induced by the absorption and metabolism of nutrients in healthy lean and obese individuals, we investigated whether ingestion of nutritive and non-nutritive sweetened beverages differentially engages the hypothalamus and brainstem vagal pathways in lean and obese women.MethodsIn a 2-day, double-blind crossover study, 11 lean and 11 obese healthy women underwent functional magnetic resonance imaging scans after ingestion of 2 beverages of different sucrose content, but identical sweetness. During scans, subjects rested with eyes closed.ResultsBlood oxygen level-dependent fluctuations demonstrated significantly greater power in the highest frequency band (slow-3: 0.073-0.198 Hz) after ingestion of high-sucrose compared with low-sucrose beverages in the nucleus tractus solitarius for both groups. Obese women had greater connectivity between the right lateral hypothalamus and a reward-related brain region and weaker connectivity with homeostasis and gustatory-related brain regions than lean women.ConclusionsIn a functional magnetic resonance imaging study, we observed sucrose-related changes in oscillatory dynamics of blood oxygen level-dependent fluctuations in brainstem and hypothalamus in lean and obese women. The observed frequency changes are consistent with a rapid vagally mediated mechanism due to nutrient absorption, rather than sweet taste receptor activation. These findings provide support for altered interaction between homeostatic and reward networks in obese individuals.

Reduction of food intake by exogenous cholecystokinin (CCK) has been demonstrated primarily for its short molecular form, CCK-8. Mounting evidence, however, implicates CCK-58 as a major physiologically active CCK form, with different neural and exocrine response profiles than CCK-8. In three studies, we compared meal-pattern effects of intraperitoneal injections CCK-8 vs. CCK-58 in undeprived male Sprague-Dawley rats consuming sweetened condensed milk. In study 1, rats (N=10) received CCK-8, CCK-58 (0.45, 0.9, 1.8 and 3.6 nmol/kg) or vehicle before a 4-h test-food presentation. At most doses, both CCK-8 and CCK-58 similarly reduced meal size relative to vehicle. Meal-size reduction prompted a compensatory shortening of the intermeal interval (IMI) after CCK-8, but not after CCK-58, which uniquely increased the satiety ratio (IMI/size of the preceding meal). In the second study, lick patterns were monitored after administration of 0.9 nmol/kg CCK-58, CCK-8 or vehicle. Lick cluster size, lick efficiency and interlick-interval distribution remained unaltered compared to vehicle, implying natural satiation, rather than illness, following both CCK forms. In study 3, threshold satiating doses of the two CCK forms were given at 5 and 30 min after meal termination, respectively. CCK 58, but not CCK-8 increased the intermeal interval and satiety ratio compared to vehicle. In conclusion, while CCK 58 and CCK-8 both stimulate satiation, thereby reducing meal size, CCK-58 consistently exerts a satiety effect, prolonging IMI. Given the physiological prominence of CCK-58, these results suggest that CCK's role in food intake regulation may require re-examination.

Abstract Background Primary care-based behavior change obesity treatment has long featured the Calorie restriction (CC), portion control approach. By contrast, the MyPlate-based obesity treatment approach encourages eating more high-satiety/high-satiation foods and requires no calorie-counting. This report describes study methods of a comparative effectiveness trial of CC versus MyPlate. It also describes baseline findings involving demographic characteristics and their associations with primary outcome measures and covariates, including satiety/satiation, dietary quality and acculturation. Methods A comparative effectiveness trial was designed to compare the CC approach (n = 130) versus a MyPlate-based approach (n = 131) to treating patient overweight. Intervenors were trained community health workers. The 11 intervention sessions included two in-home health education sessions, two group education sessions, and seven telephone coaching sessions. Questionnaire and anthropometric assessments occurred at baseline, 6- and 12 months; food frequency questionnaires were administered at baseline and 12 months. Participants were overweight adult primary care patients of a federally qualified health center in Long Beach, California. Two measures of satiety/satiation and one measure of post-meal hunger comprised the primary outcome measures. Secondary outcomes included weight, waist circumference, blood pressure, dietary quality, sugary beverage intake, water intake, fruit and vegetable fiber intake, mental health and health-related quality of life. Covariates included age, gender, nativity status (U.S.-born, not U.S.-born), race/ethnicity, education, and acculturation. Analysis Baseline characteristics were compared using chi square tests. Associations between covariates and outcome measures were evaluated using multiple regression and logistic regression. Results Two thousand eighty-six adult patients were screened, yielding 261 enrollees who were 86% Latino, 8% African American, 4% White and 2% Other. Women predominated (95%). Mean age was 42 years. Most (82%) were foreign-born; 74% chose the Spanish language option. Mean BMI was 33.3 kg/m2; mean weight was 82 kg; mean waist circumference was 102 cm. Mean blood pressure was 122/77 mm. Study arms on key baseline measures did not differ except on dietary quality and sugary beverage intake. Nativity status was significantly associated with dietary quality. Conclusions The two treatment arms were well-balanced demographically at baseline. Nativity status is inversely related to dietary quality. Trial registration NCT02514889, posted on 8/4/2015.

Introduction. The current study aimed to assess profiles of peptide YY and ghrelin, visual analog scales (VAS) for hunger and satiety, and ad libitum intake in obese and non-obese women.

Hunger and satiety are regulated in a complex fashion by a few food intake stimulatory (orexigenic) and a multitude of inhibitory (anorexigenic) factors produced in the periphery (mainly in the gastrointestinal tract) or directly in the brain. Within the brain, the hypothalamus plays a pivotal role as a production site of food intake regulatory factors. Importantly, this site integrates peripheral and central signaling factors to orchestrate food intake and in the long term body weight. Our knowledge on these regulatory pathways is not static but rather rapidly changing as new factors as well as up- and downstream signaling pathways of already known transmitters are uncovered. Hypothalamic nucleobindin2 (NUCB2), the precursor of nesfatin-1, was first described in 2006 and nesfatin-1 found to be a novel anorexigenic modulator of food intake and body weight. The initial report stimulated several groups to investigate the biological actions of nesfatin-1 and subsequent studies delineated the underlying brain mechanisms involved in its food reducing effect. Of interest was the demonstration that NUCB2 also exerts its anorexigenic action in the paraventricular nucleus of the hypothalamus and is regulated at this site by changes in metabolic status with a diurnal rhythm inversely related to that of feeding in rats. The present review describes the current state-of-knowledge on central nesfatin-1's effects on food intake and body weight and highlights important missing links regarding cellular signaling mechanisms involved in nesfatin-1's action.

Consuming foods with a form or a texture that requires longer oral processing is a way to decrease food intake. Although this approach is promising for leveraging healthier eating patterns in adults, it has never been explored in children. This study evaluated whether starting a mid-afternoon snack by eating either apple segments or applesauce would modify hunger and subsequent food intake during this meal. Forty-four children (8–10 years old) participated in two videotaped mid-afternoon snacks, during which they received one of the two forms of apple as a food preload followed 10 min later by ad libitum consumption of sweetened cottage cheese. They self-reported their level of hunger throughout consumption, and the weight of cottage cheese consumed was determined at the end of the snack. Children's chewing capabilities and eating traits were parent-reported. Eating a raw apple increased oral exposure time and decreased bite size compared to eating applesauce. However, neither the reported hunger nor consecutive food intake were modified. Regardless of the meal, children eating fast had a higher ad libitum energy intake. The individual eating rate for the cottage cheese was correlated with the eating rate observed for applesauce but not for apple segments, the latter being associated with children's chewing difficulties. This study suggests that the form of a fruit offered at the start of a mid-afternoon snack does not impact food intake; the findings clearly call for more exploration of satiation mechanisms related to food texture properties among children and indicate the need to consider children's oral processing skills.

In general, consumers enjoy products less with repeated consumption. Unfortunately, there are few known ways to slow such satiation. The authors show that consumers satiate more slowly on a product when it is available for consumption only at limited times. Specifically, they find that perceived limited availability made a product more enjoyable, and yet this effect largely emerged only after repeated consumption. The authors attribute this finding to an urge to take advantage of a rare consumption opportunity, which leads people to pay less attention to the quantity consumed and subsequently to experience less satiation. A series of studies establish the effect of perceived limited availability on the rate of satiation, show that it influences how much people eat, provide mediation evidence of the proposed theoretical account, and eliminate the effect by making salient the total amount consumed. The authors conclude with implications of these findings. [ABSTRACT FROM AUTHOR]

Reza Rastmanesh1,2 1The Nutrition Society, London, UK; 2The American Physical Society, Maryland State, MD, USACorrespondence: Reza RastmaneshPrivate Clinic, #6, Physicians Building, Sarshar Alley, Vali Asr Street, Tajrish, Tehran, 1961835555, IranEmail r.rastmanesh@gmail.com View the original paper by Dr Slyper and colleagues

Background: Short sleep is consistently linked with childhood obesity, possibly via disrupting appetite hormones and increasing food responsiveness. Few studies have objectively examined this association in early childhood., Objective: To evaluate associations of sleep quantity and quality with child appetitive traits and eating in the absence of hunger (EAH) in a higher-income cohort of 86 preschool-age children (age 4.0 ± 0.8 years; 42% female; 93% non-Hispanic white, Northern New England, US)., Methods: Children's sleep duration and quality were assessed via parent report (Children's Sleep Habits Questionnaire, CSHQ) at baseline and 6-month follow-up and via accelerometry at baseline. Parents also completed the Child Eating Behaviors Questionnaire to assess the child's appetitive traits. EAH, an objective measure of overeating, was observed at baseline during an in-person visit. Associations between sleep measures and appetitive traits were examined with linear mixed-effect or linear regression models, as appropriate, adjusting for child age, sex, and household income., Results: Shorter sleep duration per parent report was associated with less satiety responsiveness (standardized ß = 0.14, 95% CI: 0.01, 0.26; p = 0.03). Further, satiety responsiveness was inversely related to EAH (Pearson's r = -0.35, p = 0.02). No associations were found between accelerometer-measured sleep parameters and appetitive traits, and no sleep measures were related to EAH., Conclusions: Shorter usual sleep, per the parent report, was cross-sectionally associated with reduced satiety responsiveness in this sample of higher-income preschoolers. Future studies should consider whether socioeconomic status may modify the impact of poor sleep on appetitive traits in early childhood., Competing Interests: Declaration of Competing interest We declare no known conflicts of interest that may influence this research., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: The objective of the current study was to describe meal-related symptoms in youth with chronic abdominal pain fulfilling criteria for a disorder of gut-brain interaction (DGBI) and their associations with anxiety, depression, and sleep disturbances., Methods: This was a retrospective evaluation of 226 consecutive patients diagnosed with an abdominal pain-associated DGBI. As part of routine care, all had completed a standardized symptom history, the Sleep Disturbances Scale for Children (utilized to assess for disorders of initiation and maintenance of sleep and excessive daytime somnolence) and the Behavior Assessment System for Children-Third Edition (utilized to assess for anxiety and depression). Four meal related symptoms were assessed: early satiety, postprandial bloating, postprandial abdominal pain, and postprandial nausea., Results: Overall, 87.6% of patients reported at least one meal related symptom and the majority reported at least three symptoms. All meal related symptoms were significantly related to each other. Postprandial pain and nausea were more often reported by females. Early satiety, postprandial bloating, and postprandial nausea, but not postprandial pain demonstrated significant though variable associations with anxiety, depression, disorders of initiation and maintenance of sleep, and disorders of excessive somnolence, but only in adolescents., Conclusions: Meal related symptoms are very common in youth with abdominal pain-associated DGBIs. Early satiety, bloating, and postprandial nausea demonstrate variable associations with anxiety, depression, and disordered sleep while increased postprandial pain was not associated with psychologic or sleep dysfunction, suggesting a different pathway for symptom generation., (© 2024 European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Addiction poses significant social, health, and criminal issues. Its moderate heritability and early-life impact, affecting reproductive success, poses an evolutionary paradox: why are humans predisposed to addictive behaviours? This paper reviews biological and psychological mechanisms of substance and behavioural addictions, exploring evolutionary explanations for the origin and function of relevant systems. Ancestrally, addiction-related systems promoted fitness through reward-seeking, and possibly self-medication. Today, psychoactive substances disrupt these systems, leading individuals to neglect essential life goals for immediate satisfaction. Behavioural addictions (e.g. video games, social media) often emulate ancestrally beneficial behaviours, making them appealing yet often irrelevant to contemporary success. Evolutionary insights have implications for how addiction is criminalised and stigmatised, propose novel avenues for interventions, anticipate new sources of addiction from emerging technologies such as AI. The emerging potential of glucagon-like peptide 1 (GLP-1) agonists targeting obesity suggest the satiation system may be a natural counter to overactivation of the reward system., Competing Interests: Conflict of interest None, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Calorie content and hunger are two fundamental cues acting upon the processing of visually presented food items. However, whether and to which extent they affect visual awareness is still an open question. Here, high- and low-calorie food images administered to hungry or satiated participants were confronted in a breaking-Continuous Flash Suppression paradigm (Experiment 1), measuring the time required to access to visual awareness, and in a Binocular Rivalry paradigm (Experiment 2), quantifying the dominance time in visual awareness. Experiment 1 showed that high-calorie food accessed faster visual awareness, but mostly in satiated participants. Experiment 2 indicated that high-calorie food dominated longer visual awareness, regardless the degree of hunger. We argued that the unconscious advantage (Experiment 1) would represent a default state of the visual system towards highest-energy nutrients, yet the advantage is lost in hunger so to be tuned towards an increased need for any nutritional category. On the other hand, the conscious advantage of high-calorie food (Experiment 2) would represent a conscious perceptual and attentional bias towards highest energy-dense food useful for the actual detection of these stimuli in the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Models in which current utility depends solely on current consumption (a.k.a. time-separable preferences) are widely acknowledged to be unrealistic, especially when attempting to describe preferences over consumption rates. Alternatively, one may stipulate that instant utility also depends on a state, for example, some stock of past consumption. Escaping the gravitational pull of time separability, however, is difficult because (1) the behavioral axioms that characterize the state and the instant utility are not known, (2) how to elicit the preference parameters—most notably the initial level of the state and the decay rate—is not known, and (3) managerial applications where state-dependent preferences produce interesting insights and solutions are scarce. This paper makes advances on these three fronts by proposing a novel set of axioms that characterize the satiation model, a proof of concept on how to elicit all preference parameters using consumption rates, and a mixed-integer linear formulation to solve the optimal design of experiential services under satiation. Our preferences introduce a de-satiation motive, absent in separable preferences, and we explore how to optimally manage this motive. This paper was accepted by David Simchi-Levi, decision analysis. [ABSTRACT FROM AUTHOR]

Introduction: The aim of the present study was to evaluate if the pasta quality is decisive in controlling hunger and satiety compared with rice. Material and methods: n=16 (8 men, 8 women). The effect on appetite and satiety of two different-quality pastas and also rice was determined by repeated measuring. Subjects came on fasting and were evaluated at different times after the intake of product under investigation for 240 min, eaten an ad libitum buffet and were evaluated again at minute 270. Aspects related to satiety (hunger, satiety, fullness, and desire to eat) were evaluated by visual analog scale (VAS), overall appetite score (OAS), area under curve (AUC) and satiety quotient (SQ). Results: The OAS reported by volunteers prior to the intake of products under investigation did not differ significantly, so baseline parameters did not bias later measurements. AUC after 60 minutes was higher after the intake of rice (2355 ±1556%/min) compared with both types of pasta. On the other hand, similar values were obtained between the two types of pasta (pasta A = 1808 ± 1329 % /min; pasta B = 1,774 ± 1,370%/min). Further, AUC reported by volunteers after 240 minutes was higher after the intake of rice (12,424 ± 6,187%/min) compared with both types of pastas (pasta A = 10,292 ± 5,410%/min; pasta B = 9,976 ± 5,589%/min). In addition, SQ was lower for rice (1.90 ± 4.29%/kcal) than for both pastas (pasta A = 4.73 ± 4.95%/kcal; pasta B = 4.40 ± 5.14%/kcal). Conclusions: Both varieties of pasta showed higher satiety results than rice, with no significant difference between them. In addition, the difference between rice and pasta was greater within 60 minutes after ingestion.

When asked to select several options at once, people tend to choose a greater diversity of items than when they are asked to make these selections one at a time. Using functional magnetic resonance imaging (fMRI), we provide novel insight into the neural mechanisms underlying diversification in portfolio choices. We found that, as participants made multiple selections from a menu of different options, the current state of their choice portfolio (i.e., the previously selected options) dynamically modulates activity in the neural valuation system in response to the options under evaluation. More specifically, we found that activity in the ventral striatum (VS) decreases when the option has already been selected (“satiation”), while activity in the ventromedial prefrontal cortex increases when other options have previously been selected (“novelty-seeking”). Our findings reveal two processes that drive diversification in portfolio choices, and suggest that the context of previous selections strongly impacts how the brain evaluates current choice options.

From humans to vinegar flies, exposure to diets rich in sugar and fat lowers taste sensation, changes food choices, and promotes feeding. However, how these peripheral alterations influence eating is unknown. Here we used the genetically tractable organism D. melanogaster to define the neural mechanisms through which this occurs. We characterized a population of protocerebral anterior medial dopaminergic neurons (PAM DANs) that innervates the β’2 compartment of the mushroom body and responds to sweet taste. In animals fed a high sugar diet, the response of PAM-β’2 to sweet stimuli was reduced and delayed, and sensitive to the strength of the signal transmission out of the sensory neurons. We found that PAM-β’2 DANs activity controls feeding rate and satiation: closed-loop optogenetic activation of β’2 DANs restored normal eating in animals fed high sucrose. These data argue that diet-dependent alterations in taste weaken satiation by impairing the central processing of sensory signals.

The aim of this study was to evaluate the ability of mid-infrared (MIR) spectroscopy combined with chemometrics to analyze unstimulated saliva as a method to predict satiety in healthy participants. This study also evaluated features in saliva that were related to individual perceptions of human–food interactions. The coefficient of determination (R2) and standard error in cross validation (SECV) for the prediction of satiety in all saliva samples were 0.62 and 225.7 satiety area under the curve (AUC), respectively. A correlation between saliva and satiety was found, however, the quantitative prediction of satiety using unstimulated saliva was not robust. Differences in the MIR spectra of saliva between low and high satiety groups, were observed in the following frequency ratios: 1542/2060 cm−1 (total protein), 1637/3097 cm−1 (α-amino acids), and 1637/616 (chlorides) cm−1. In addition, good to excellent models were obtained for the prediction of satiety groups defined as low or high satiety participants (R2 0.92 and SECV 0.10), demonstrating that this method could be used to identify low or high satiety perception types and to select participants for appetite studies. Although quantitative PLS calibration models were not achieved, a qualitative model for the prediction of low and high satiety perception types was obtained using PLS-DA. Furthermore, this study showed that it might be possible to evaluate human/food interactions using MIR spectroscopy as a rapid and cost-effective tool.

Previous work has ostensibly shown that readers rapidly adapt to less predictable ambiguity resolutions after repeated exposure to unbalanced statistical input (e.g., a high number of reduced relative-clause garden-path sentences), and that these readers grow to disfavor the a priori more frequent (e.g. main verb) resolution after exposure (Fine, Jaeger, Farmer, & Qian, 2013). However, recent work has failed to replicate effects indicating a penalty for the a priori preferred, more frequent continuation, despite finding a speedup in syntactic repair times after initial exposure to the dispreferred, infrequent structure (Harrington Stack, James, & Watson, 2018). The current study reports three self-paced reading experiments that test whether co-occurring cues (explicit comprehension questions, preceding semantic cues, and font color) help facilitate adaptation to reduced relative/main verb garden-path sentences. Results suggest that readers do not overcome preexisting expectation biases by rapidly adapting to statistically novel linguistic contexts even with convergent probabilistic cues. An emphasis is placed on the difference between syntactic satiation effects and expectation adaptation, the latter of which we argue can only be determined through a penalty for an a priori preferred resolution after repeated exposure to its a priori less-preferred counterpart. [ABSTRACT FROM AUTHOR]

In group-living species, particularly cooperative breeders, all group members contribute to various behaviours but there is considerable variation between and within individuals in their contributions. While it is well established that there is variation due to differences in the costs and benefits for individuals of different sex, age and dominance status, shorter-term social, internal and environmental factors are also likely to be important. Sentinel behaviour, where individuals adopt a raised position to scan for danger while groupmates forage, offers an opportunity to test hypotheses about context-dependent differences in contributions to group behaviour. Here we used field experiments to manipulate the conspecific audience, satiation state and perceived danger level of dwarf mongooses, Helogale parvula , to investigate how sentinel contributions are modulated by individual context. In addition to standard measures of sentinel behaviour (likelihood of becoming a sentinel, number of bouts, bout duration), we considered within-bout behaviour in terms of surveillance calls and attentiveness (head-scanning rate and distraction levels). We found that the presence of a neighbouring forager (audience) decreased sentinel contributions, while individuals increased their sentinel investment when satiated and experiencing an increased danger level. Changes in head-scanning rate provided evidence for an interaction between the effect of satiation and danger levels, demonstrating that sentinel attentiveness was influenced by changes in context. Our results demonstrate that sentinel behaviour is strongly context dependent, with effects seen in initial bout and bout quantity decisions, as well as within-bout characteristics, and that individual contributions to group behaviours can vary depending on social, internal and environmental factors. • Sentinel contributions are modified by social, internal and environmental factors. • Changes seen across behavioural levels: initial bout, bout quantity and within bouts. • Simulated close audience decreased sentinel contributions. • Supplementary feeding and alarm call playback increased sentinel contributions. • Attentiveness of a sentinel can change with differing context. [ABSTRACT FROM AUTHOR]

Memory and cognitive processes influence the amount of food consumed during a meal, yet the neurobiological mechanisms mediating these effects are poorly understood. The hippocampus (HPC) has recently emerged as a brain region that integrates feeding-relevant biological signals with learning and memory processes to regulate feeding. We investigated whether the gut-derived hormone ghrelin acts in the ventral HPC (vHPC) to increase meal size through interactions with gut-derived satiation signaling. Interactions between vHPC ghrelin signaling, gut-derived satiation signaling, feeding, and interoceptive discrimination learning were assessed via rodent behavioral neuropharmacological approaches. Downstream neural pathways were identified using transsynaptic virus-based tracing strategies. vHPC ghrelin signaling counteracted the food intake–reducing effects produced by various peripheral biological satiation signals, including cholecystokinin, exendin-4 (a glucagon-like peptide-1 receptor agonist), amylin, and mechanical distension of the stomach. Furthermore, vHPC ghrelin signaling produced interoceptive cues that generalized to a perceived state of energy deficit, thereby providing a potential mechanism for the attenuation of satiation processing. Neuroanatomical tracing identified a multiorder connection from vHPC neurons to lateral hypothalamic area orexin (hypocretin)-producing neurons that project to the laterodorsal tegmental nucleus in the hindbrain. Lastly, vHPC ghrelin signaling increased spontaneous meal size via downstream orexin receptor signaling in the laterodorsal tegmental nucleus. vHPC ghrelin signaling increases meal size by counteracting the efficacy of various gut-derived satiation signals. These effects occur via downstream orexin signaling to the hindbrain laterodorsal tegmental nucleus, thereby highlighting a novel hippocampus-hypothalamus-hindbrain pathway regulating meal size control. [ABSTRACT FROM AUTHOR]

Background: Subjective stress is a well-documented predictor of early smoking relapse, yet our understanding of stress and tobacco use is limited by reliance on self-reported measures of stress. We utilized a validated functional neuroimaging paradigm to examine whether stress exposure during early abstinence alters objective measures of brain function.Methods: Seventy-five participants underwent blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) during the Montreal Imaging Stress Task (MIST) on two occasions: once during smoking satiety and once following biochemically confirmed 24-hour abstinence (order counterbalanced). The primary outcome measure was brain response during stress (vs. control) blocks of the MIST, assessed using whole-brain analysis corrected for multiple comparisons using clusters determined by Z ≥ 3.1.Results: Abstinence (vs. satiety) was associated with significantly increased activation in the left inferior frontal gyrus, a brain region associated with inhibitory control. Abstinence-induced change in brain response to stress was positively associated with change in self-reported stress.Conclusions: This study provides objective evidence that the brain response to stress is altered during the first 24 hours of a quit attempt compared to smoking satiety.Implications: These results point to the potential value of inoculating smokers with stress management training prior to a quit attempt. [ABSTRACT FROM AUTHOR]