Levels Of Food Deprivation Research Articles

No food for thought: An intermediate level of food deprivation enhances memory in Lymnaea.

Nutritional status plays an important role in cognitive functioning but there is disagreement on the role that food deprivation plays in learning and memory. In this study, we investigated the behavioral and transcriptional effects induced by different lengths of food deprivation: 1 day, which is a short-time period of food deprivation, and 3 days, which is an 'intermediate' level of food deprivation. Snails were subjected to different feeding regimens and then trained for operant conditioning of aerial respiration where they received a single 0.5h training session followed by a long-term memory (LTM) test 24h later. Immediately after the memory test, snails were sacrificed and the expression levels of key genes for neuroplasticity, energy balance, and stress response were measured in the central ring ganglia. We found that 1 day of food deprivation was not sufficient to enhance snails' LTM formation and subsequently did not result in any significant transcriptional effects. However, 3 days of food deprivation resulted in enhanced LTM formation and caused the upregulation of neuroplasticity and stress-related genes and the downregulation of serotonin-related genes. These data provide further insight into how nutritional status and related molecular mechanisms impact cognitive function.

Efectos de variar el nivel de privación de comida sobre el valor reforzante del agua en el beber inducido por el programa

Scheduled-induced drinking (SID) occurs when food-deprived rats are exposed to intermittent schedules of food reinforcement. In recent years, SID has been considered as operant behavior reinforced directly by water and it has been suggested that food deprivation may function as a motivating operation that increases the reinforcing value of water. The purpose of the study was to determine the effects of varying food-deprivation levels on water reinforcing efficacy during SID sessions. In successive phases, three rats were maintained at their free-feeding weights, or were food deprived at 90 or 80% of their free-feeding weights. Rats were exposed to SID sessions in which food was delivered according to a tandem fixed- time 176- s, differential-reinforcement-of-other-behavior 4-s. Lever presses were reinforced with water according to a progressive-ratio 5 schedule. In general, response rates for water and break points increased with increases in food-deprivation level. The results complement earlier findings showing that SID is operant behavior reinforced directly by water.

Assessment of Food and Nutrition Insecurity using Food Consumption Data in Central Sudan

This study aims to assess the food and nutrition insecurity among different income quintiles in Central Sudan. Particularly, it seeks to determine the level of dietary energy consumption (DEC) and other macronutrients intake. In addition, it estimates the Engel ratios and income elasticity of food demand. A sample of about 668 households was selected from Khartoum State to collect the primary data during the year 2017. Primary data was collected through two types of questionnaires, the structured household questionnaire, and the 24-hour food recall questionnaire. The data was analyzed using descriptive statistics and One-way ANOVA Table. The outcomes prove that income contributes extensively to DEC as well as intakes of protein, carbohydrates, and fat. The households in the lowest income quintile spend a high monetary value to purchase foods when compared with households in other income quintiles. The Engel ratios exhibit that the share of food consumption from the total income for the lowest income quintile is about 62%, which is higher relative to the highest income quintile (43.6%). In addition, Engel ratios varies significantly among the income quintiles at level 1%. The income elasticity of food demand in dietary energy consumption is higher for the lowest income quintile (0.49) than the highest income quintile (0.23). This indicates that a little increase in income will contribute significantly to better nutritional status for the lowest income quintile. Eventually, the paper recommends improving income earnings through income-based policies to reduce the level of food deprivation. The government should adopt specific market policies that focus on the low-income level to enhance access to nutritious foods.

Foraging and feeding are independently regulated by social and personal hunger in the clonal raider ant

Ant colonies must assess the internal states of their members and coordinate their responses to changes in state. One important example of this is the sensing of colony hunger and the regulation of foraging behavior. In many ant species, workers’ own nutritional states at least partially determine how much they forage, and poorly nourished workers usually forage more, while well-nourished workers remain inside the nest. Workers in some species, such as the clonal raider ant Ooceraea biroi, mostly forage in response to larval signals. Here, we ask whether O. biroi larvae directly affect worker nutrition, and whether nutritional states in turn regulate workers’ foraging and feeding behavior. We find that larval signals do not detectably influence workers’ nutritional states or feeding behavior. Unlike in most other ant species, however, when colonies forage in response to larval signals, better-nourished O. biroi workers forage more. This suggests evolutionary modifications to the nature and strength of the relationship between nutritional state and foraging behavior in some ants. Nonetheless, worker nutritional states regulate feeding behavior as expected, with workers eating in proportion to their level of food deprivation. We discuss the implications of these results for the life history of O. biroi and the evolution of foraging regulation in social insects more generally. We suggest that the decoupling of regulatory mechanisms for feeding and foraging has parallels in the evolutionary elaboration of animal multicellularity. Foraging in social insects is a cooperative behavior: workers forage for the colony, rather than just for themselves. In most species, workers primarily use their own hunger as proxies for the colony’s needs. However, some species use other sources of information. Clonal raider ants, for example, forage in response to signals from their larvae. Here, we ask whether they also forage when deprived of nutrition. Surprisingly, we find instead that they forage more when better fed, and that in unmanipulated colonies, larval signals override worker nutrition, suggesting that the regulation of foraging has been rewired in this species. We also find that workers feed in proportion to their nutrient deprivation, suggesting that the regulation of feeding has been conserved. We propose that the uncoupling of feeding and foraging machinery has parallels in the evolutionary elaboration of animal multicellularity.

Inhibition of Itch by Hunger and AgRP Neuron Activity

Unpleasant somatosensory stimuli such as pain and itch can interrupt normal behavior. But survival can depend on resuming normal behavior before these challenges are fully resolved. The neural mechanisms that prioritize behavior when individuals are challenged with unpleasant somatosensory sensations, however, are not fully understood. Recently, we identified a neural circuit activated by hunger that can inhibit pain, prioritizing food seeking over tending to an injury. Here, we examine the ability of hunger, and neurons activated by hunger, to inhibit behavioral responses to another unpleasant somatosensory sensation – itch. We demonstrate that food deprivation inhibits scratching induced by three different pruritogenic stimuli: histamine, serotonin, and chloroquine. The inhibition of scratching correlates with the level of food deprivation, suggesting a cross-competition of alarm systems in the brain whereby more energy need more efficiently inhibits competing drives. Finally, we show that activity in hunger-sensitive, hypothalamic agouti-related protein (AgRP)-expressing neurons is sufficient to inhibit itch. Taken together, we showed that hunger or AgRP neuron activity inhibits itch, demonstrating that organisms have neural systems to filter and process ascending spinal signals activated by unpleasant somatosensory stimuli to prioritize salient needs.

Self-restraint spillover: Inhibitory control disrupts appetite regulation among ruminators.

People can use inhibitory control to temporarily inhibit their personal preferences to achieve their long-term goals. According to the ego fixation model (Koole et al., 2014), ruminators have difficulties relaxing inhibitory control, leading them to continue inhibiting their personal needs, even when this is no longer required by the situation. Inhibitory control may thus disrupt healthy appetite regulation among ruminators. Among 324 Dutch undergraduate students (218 women; Mage = 21.5), different inhibitory control states were manipulated by varying whether or not participants exerted inhibitory control (Study 1) or priming high versus low inhibitory control (Study 2). All participants then performed a food-tasting task. Healthy appetite regulation was defined as a positive correlation between level of food deprivation and preference for high-calorie foods. For taste ratings, the interaction between inhibitory control and rumination was significant in each study: Inhibitory control disrupted healthy appetite regulation in taste preferences among ruminators, but not among non-ruminators. For eating behavior, the same interaction effect was significant when the two studies were combined. Inhibitory control disrupts healthy appetite regulation among ruminators. These findings suggest the need for caution in interventions that rely on inhibitory control, especially among samples with compulsive thought tendencies.

Discriminative control by deprivation states and external cues in male and female rats

Previous research indicates that decisions about when to eat in response to food cues in the environment are based on interoceptive energy states (i.e., hunger and fullness) and learning about and remembering prior eating experiences. However, this animal model has exclusively been tested on male rodents. Despite evidence that women are more susceptible to obesity and cognitive disorders associated with excess weight (e.g., Alzheimer's disease) than men, the generality of these findings with males to females remains unknown. To address this gap, the current research investigated associative learning mechanisms involved in food intake control in females by training both males and females in a Pavlovian deprivation discrimination in which varying levels of food deprivation are trained with competitive external cues to signal reward. In Experiment 1, male and female rats showed similar performance in discriminating between 0 and 24h deprivation state/external cue compounds and in subsequent tests, confirming stimulus control by deprivation states. Experiment 2 assessed learning about more ecologically valid 0 and 4h deprivation states in competition with external cues in both males and females. With the low-level deprivation state parameters, females outperformed males in discriminative control by deprivation states, particularly on the contingency rewarded under satiation and not deprivation. While females showed an enhanced degree of energy state processing under some deprivation conditions, overall, these findings suggest similar mechanisms of learned appetitive control in both sexes.

Nest‐dwelling ectoparasites reduce begging effort in Pied Flycatcher Ficedula hypoleuca nestlings

Parasitized nestlings might be expected to increase begging effort to obtain additional resources to compensate for those sequestered by their parasites. However, begging is costly and chicks harbouring parasites may find it more difficult to attain high begging levels. Consequently, we predicted that, for the same level of nutritional need, nestlings that are parasitized will invest less in begging than those that are not parasitized. We tested this prediction by measuring begging in Pied Flycatcher Ficedula hypoleuca nestlings parasitized with haematophagous mites Dermanyssus gallinoides and Dermanyssus gallinae and blowfly larvae Protocalliphora azurea, and subjected to different levels of food deprivation in order to control for short‐term nutritional need. Nestlings from nests with ectoparasites spent less time begging than those from nests without parasites, especially when very hungry, although there was no association with latency to beg or begging intensity. Our results suggest that time invested in begging may indicate not only the level of need, but also nestling parasitism status.

Interval timing under a behavioral microscope: Dissociating motivational and timing processes in fixed-interval performance.

The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30s and FI 90s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies is sensitive to the periodicity of reinforcement, and prefeeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Prefeeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, latency and IRT models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI schedules fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance. These processes may be obscured, however, when performance in timing tasks is analyzed in terms of mean response rates.

Multidimensional poverty in urban Brazil: income, assets and expenses

Purpose– The purpose of this paper is to present deprivation in urban Brazil in a multidimensional perspective with dimensions related to household’s objective information, assets in the household, subjective evaluation concerning the dwelling and expenses.Design/methodology/approach– The author used factorial analysis applied to the Brazilian Household Budget Survey. Most dimensions showed a positive correlation with income, while for others it was not observed any significant difference between income ranges. Some types of deprivation specially touched low-income households, while other dimensions differentiated middle-income households, or even higher income households. The author applied a fuzzy perspective to define deprivation membership in each dimension with the use of a modified logistic function. The author observed that households with similar income faced different levels of deprivation in many dimensions.Findings– The author showed that there were significant differences in household’s expense preferences and profiles linked to these findings. Households with high levels of food deprivation relatively spend more on household’s rent, taxes and services, indicating that shelter and then food in the household are the very basic goods. Larger relative expenses with food in the household indicated higher levels of deprivation in all other dimensions, indicating that due to these higher food expenditures, the households could not overcome the deprivation in other dimensions. Households that spend more on smoke and gambling faced higher deprivation in most dimensions, suggesting different expenses priorities, less household oriented.Originality/value– To the best of the knowledge, this is the first attempt to link multidimensional deprivation and expenses profile for Brazilian data.

The impact of health claims and food deprivation levels on health risk perceptions of fast-food restaurants

Objective and procedureWe examined the effect of health claims and food deprivation levels on the health risk perceptions of fast-food restaurants. Consistent with previous research, we used a within-subjects experimental design to manipulate the health claims of fast-food restaurants using real brands: Subway, expressing strong health claims vs. McDonald's, expressing weak health claims. Participants who did not have access to nutrition information were asked to estimate the health risk associated with food items that were slightly more caloric for Subway than McDonald's (640 kcal vs. 600 kcal). We collected data through a web survey with a sample consisting of 414 American adults. Based on the USDA Food Insufficiency Indicator, participants were classified into two categorical food deprivation levels: food sufficiency and food insufficiency. Results and conclusionsWe find that risk perceptions for obesity, diabetes and cardiac illnesses are lower (higher) for the restaurant with stronger (lower) health claims, i.e., Subway (McDonald's). Moreover, we also find that food deprivation levels moderate this effect, such that health risk underestimation is aggravated for individuals who suffer from food insufficiency. More precisely, we find that food insufficient individuals are more responsive to health claims, such that they perceive less health risk than food sufficient individuals for the restaurant with stronger health claims (Subway). Exploring the underlying mechanism of the latter effect, we found that dietary involvement mediates the relationship between food deprivation levels and health risk perceptions for the restaurant with stronger health claims (Subway). These results provide an interdisciplinary contribution in consumer psychology and public health.

A novel strategy for dissecting goal-directed action and arousal components of motivated behavior with a progressive hold-down task.

Motivation serves 2 important functions: It guides actions to be goal-directed, and it provides the energy and vigor required to perform the work necessary to meet those goals. Dissociating these 2 processes with existing behavioral assays has been a challenge. In this article, we report a novel experimental strategy to distinguish the 2 processes in mice. First, we characterize a novel motivation assay in which animals must hold down a lever for progressively longer intervals to earn each subsequent reward; we call this the progressive hold-down (PHD) task. We find that performance on the PHD task is sensitive to both food deprivation level and reward value. Next, we use a dose of methamphetamine (METH) 1.0 mg/kg, to evaluate behavior in both the progressive ratio (PR) and PHD tasks. Treatment with METH leads to more persistent lever pressing for food rewards in the PR. In the PHD task, we found that METH increased arousal, which leads to numerous bouts of hyperactive responding but neither increases nor impairs goal-directed action. The results demonstrate that these tools enable a more precise understanding of the underlying processes being altered in manipulations that alter motivated behavior.

Western-style diet impairs stimulus control by food deprivation state cues: Implications for obesogenic environments

In western and westernized societies, large portions of the population live in what are considered to be “obesogenic” environments. Among other things, obesogenic environments are characterized by a high prevalence of external cues that are associated with highly palatable, energy-dense foods. One prominent hypothesis suggests that these external cues become such powerful conditioned elicitors of appetitive and eating behavior that they overwhelm the internal, physiological mechanisms that serve to maintain energy balance. The present research investigated a learning mechanism that may underlie this loss of internal relative to external control. In Experiment 1, rats were provided with both auditory cues (external stimuli) and varying levels of food deprivation (internal stimuli) that they could use to solve a simple discrimination task. Despite having access to clearly discriminable external cues, we found that the deprivation cues gained substantial discriminative control over conditioned responding. Experiment 2 found that, compared to standard chow, maintenance on a “western-style” diet high in saturated fat and sugar weakened discriminative control by food deprivation cues, but did not impair learning when external cues were also trained as relevant discriminative signals for sucrose. Thus, eating a western-style diet contributed to a loss of internal control over appetitive behavior relative to external cues. We discuss how this relative loss of control by food deprivation signals may result from interference with hippocampal-dependent learning and memory processes, forming the basis of a vicious-cycle of excessive intake, body weight gain, and progressive cognitive decline that may begin very early in life.

Individual differences in novelty-seeking are associated with different patterns of preference in a risk-sensitivity procedure in rats

The preferences of organisms faced with changing conditions in food delivery situations have been studied under the rubric of risk-sensitivity. Optimal foraging theory often applies the energy budget model to explain the preferences shown by organisms, but in this paper we suggest a different approach, one based on the study of individual differences. A sample of rats was classified as high and low novelty-seeking. Afterwards, they were maintained at 75% or 90% of their body weight and exposed to a risk-sensitivity procedure. The results show that the novelty-seeking model is associated with different patterns of preference under a risk-sensitivity procedure, but that these patterns do not correlate with the level of food deprivation employed. Furthermore, we found that the spontaneous alternation between options in a choice situation correlates with the organism’s preference during a risk procedure. Considering recent findings in the area of animal and human decision-making, our results are explained in terms of altered behavioral processes.

Choice and timing in pigeons under differing levels of food deprivation

State-dependent valuation learning (SDVL) is a preference for stimuli associated with relative food deprivation over stimuli associated with relative satiety. Pigeons were exposed to experimental conditions designed to investigate SDVL and to test the hypothesis that obtained relative immediacy during training predicts choice during test probes. Energy states were manipulated using a procedure that has previously revealed SDVL in starlings and pigeons. In Experiment 1, pigeons preferred the stimulus associated with deprivation in the first choice probe session, but were indifferent in the second. Changes in choice were consistent with changes in obtained relative immediacy. In Experiment 2, training parameters were altered and SDVL did not occur. Obtained relative immediacy again predicted choice. Results of both experiments provide evidence that obtained relative immediacy may be an important contributing factor to the SDVL phenomenon.

Do impaired memory and body weight regulation originate in childhood with diet-induced hippocampal dysfunction?

Do impaired memory and body weight regulation originate in childhood with diet-induced hippocampal dysfunction?

Combined effects of food deprivation and food frequency on the amount and temporal distribution of schedule‐induced drinking

Under intermittent food schedules animals develop temporally organized behaviors throughout interfood intervals, with behaviors early in the intervals (interim) normally occurring in excess. Schedule-induced drinking (a prototype of interim, adjunctive behavior) is related to food deprivation and food frequency. This study investigated the interactions that resulted from combining different food-deprivation levels (70%, 80% or 90% free-feeding weights) with different food-occurrence frequencies (15-, 30- or 60-s interfood intervals) in a within-subjects design. Increases in food deprivation and food frequency generally led to increased licking, with greater differences due to food deprivation as interfood intervals became shorter. Distributions of licking were modestly shifted to later in the interfood interval as interfood intervals lengthened, a result that was most marked under 90% food deprivation, which also resulted in flatter distributions. It would therefore appear that food deprivation modulates the licking rate and the distribution of licking in different ways. Effects of food deprivation and food frequency are adequately explained by a theory of adjunctive behavior based on delayed food reinforcement, in contrast to alternative hypotheses.

Warning color changes in response to food deprivation in the pipevine swallowtail butterfly, Battus philenor.

Predation on distasteful animals should favor warning coloration that is relatively conspicuous and phenotypically invariable. However, even among similarly colored individuals there can be variation in their warning signals. In butterflies, individual differences in larval feeding history could cause this variation. The warning signal of the pipevine swallowtail butterfly, Battus philenor L. (Lepidoptera: Papilionidae) consists of both a blue iridescent patch and pigmentbased orange spots on the ventral hindwing. B. philenor males also display a dorsal surface iridescent patch that functions as a sexual indicator signal. A previous study of iridescence in B. philenor found that the iridescent blue on both the dorsal and ventral hind wings is variable and significantly different between lab-reared and field-caught individuals. These differences could be the result of larval food deprivation in the field. Through experimental manipulation of larval diet, larval food deprivation was evaluated as a potential cause of the differences observed between lab and field individuals, and if food deprivation is a source of inter-individual variation in warning signals. B. philenor larvae were food restricted starting at two points in the last larval instar, and one group was fed through pupation. Adult coloration was then compared. Food deprivation led to poorer adult condition, as indicated by lower adult body mass, forewing length, and fat content of stressed individuals. As the level of food deprivation increased, the hue of the iridescent patches on both the dorsal and ventral hind wing shifted to shorter wavelengths, and the chroma of the orange spots decreased. The shifts in iridescent color did not match the differences previously found between lab and field individuals. However, the treatment differences indicate that food deprivation may be a significant source of warning color variation. The differences between the treatment groups are likely detectable by predators, but the effect of the variation on signal effectiveness and function remains to be empirically explored.

Decreased consumption of sweet fluids in mu opioid receptor knockout mice: a microstructural analysis of licking behavior

Evidence suggests that the palatability of food (i.e., the hedonic impact produced by its sensory features) can promote feeding and may underlie compulsive eating, leading to obesity. Pharmacological studies implicate opioid transmission in the hedonic control of feeding, though these studies often rely on agents lacking specificity for particular opioid receptors. Here, we investigated the role of mu opioid receptors (MORs) specifically in determining hedonic responses to palatable sweet stimuli. In Experiment 1, licking microstructure when consuming sucrose solution (2 to 20%) was compared in MOR knockout and wildtype mice as a function of sucrose concentration and level of food deprivation. In Experiment 2, a similar examination was conducted using the palatable but calorie-free stimulus sucralose (0.001 to 1%), allowing study of licking behavior independent of homeostatic variables. In Experiment 1, MOR knockout mice exhibited several alterations in sucrose licking. Although wildtype mice exhibited a twofold increase in the burst length when food deprived, relative to the nondeprived test, this aspect of sucrose licking was generally insensitive to manipulations of food deprivation for MOR knockout mice. Furthermore, during concentration testing, their rate of sucrose licking was less than half that of wildtype mice. During sucralose testing (Experiment 2), MOR knockout mice licked at approximately half the wildtype rate, providing more direct evidence that MOR knockout mice were impaired in processing stimulus palatability. These results suggest that transmission through MORs mediates hedonic responses to palatable stimuli, and therefore likely contributes to normal and pathological eating.

Effect of voluntary physical exercise and post-training epinephrine on acquisition of a spatial task in the barnes maze

A number of experiments have shown that physical exercise improves acquisition and retention for a variety of learning tasks in rodents. Most of these works have been conducted with tasks associated with a considerable level of stress, physical effort and/or food deprivation that might interact with exercise, thus hindering the interpretation of the results. On the other hand, it is well established that post-training epinephrine is able to facilitate memory consolidation, but only a few works have studied its effect on the process of acquisition. The present work was aimed at studying whether 17 days of voluntary physical exercise (running wheels) and/or post-training epinephrine (0.01 or 0.05mg/kg) could improve the acquisition of a spatial task in the Barnes maze, and whether the combination of the two treatments have additive effects. Our results showed that exercise improved acquisition, and 0.01mg/kg of epinephrine tended to enhance it, by reducing the distance needed to find the escape hole. The combination of both treatments failed to further improve the acquisition level. We concluded that both treatments exerted their effect on acquisition by enhancing the process of learning itself, and that exercise is able to improve acquisition even using tasks with a low level of stress and physical effort.