Taste aversion learning during successive negative contrast.

Previous experiments found that acceptance of saccharin by rats was reduced if they had prior experience of sucrose or some other highly palatable solution. This study tested whether such successive negative contrast (SNC) effects involve acquisition of an aversion to the new taste. In three experiments, rats were switched from sucrose exposure in Stage 1 to a less palatable solution containing a new taste in Stage 2.

Switching from sucrose to saccharin: Extended successive negative contrast is not maintained by hedonic changes.

Previous experiments found that acceptance of saccharin by rats was reduced if they had prior experience of sucrose or some other highly palatable solution. This reduction in saccharin consumption was particularly extended after a switch from sucrose. On the surface, this seems to correspond to a successive negative contrast (SNC) effect.

Does drinking saccharin weaken an association of sweet with calories? Pre-exposure effects in flavor preference learning.

The main aim of this experiment was to examine the claim that exposure to non-nutritive sweeteners weakens the formation of a sweet-calorie association. Three groups of food-deprived rats received training in which they drank an almond-flavored maltodextrin and saccharin solution. A final test phase assessed their preference for almond.

Switching from Sugar- to Artificially-Sweetened Beverages: A 12-Week Trial.

Background: Consumption of sugar-sweetened beverages (SSBs) forms the primary source of added sugar intake and can increase the risk of metabolic disease. Evidence from studies in humans and rodents also indicates that consumption of SSBs can impair performance on cognitive tests, but that removing SSB access can ameliorate these effects.

Methods: The present study used an unblinded 3-group parallel design to assess the effects of a 12-week intervention in which young healthy adults (mean age = 22.

Unpredictability of access to a high fat/high sugar food can increase rats' intake.

When food is readily available, human self-imposed restrictions on consumption of palatable foods can lead to binge eating. Rodent models of human bingeing have produced increased intakes. However, access to highly palatable foods in such models has been largely predictable.

Reduction in caffeine withdrawal after open-label decaffeinated coffee.

Background: Withdrawal from addictive drugs can be reduced by administering placebo deceptively, but in the clinic it is unethical to deceive the patient. Open-label placebo effects have been observed across a range of psychophysiological phenomena, and may also apply to drug withdrawal.

Method: 24-hour abstinent heavy coffee drinkers ( = 61) rated their caffeine withdrawal symptoms before being allocated to one of three groups.

A systematic review and meta-analysis of animal models of binge eating - Part 1: Definitions and food/drink intake outcomes.

Binge eating involves consuming excessive amounts of food within a discrete period of time and is associated with significant impairments in binge-eating disorder and bulimia nervosa. While research on clinical binge eating has provided valuable aetiological insights, animal models allow for closer examination of environmental, biological, and developmental risk factors. Numerous animal models of binge eating exist and differ widely in operational definitions of bingeing, animal characteristics and methodological parameters.

Sucrose intake by rats affected by both intraperitoneal oxytocin administration and time of day.

Rationale: Daily limited access to palatable food or drink at a fixed time is commonly used in rodent models of bingeing. Under these conditions, entrainment may modulate intake patterns. Oxytocin is involved in circadian patterns of intake and, when administered peripherally, reduces sucrose intake.

Caffeine-based flavor preference conditioning in the rat.

The massive consumption of caffeine-containing beverages has prompted many studies involving human participants that have obtained caffeine-based increases in liking for a flavor. However, few studies have succeeded in obtaining caffeine-based flavor preference learning in rats. The main aim of the present study was to examine the conditions under which such learning can be detected.

Sucrose-based flavor preferences in rats: Factors affecting detection of extinction.

Rats that have consumed a novel target flavor added to a sucrose solution will develop a preference for that flavor. Such preferences appear to persist over the course of many presentations of the flavor alone when animals are not food-deprived. However, previous research indicates that an extinction effect (a reduction in preference) can be obtained when training or testing is carried out in animals that are hungry.

Sex differences in recovery from cognitive and metabolic impairments induced by supplementary sucrose in rats.

Consumption of beverages containing around 10% sucrose contributes to worldwide obesity. Studies using rats can increase understanding of the consequences of such consumption. The present experiment aimed to compare male and female rats, first, in terms of cognitive and metabolic impairments produced by excessive intakes of 10% sucrose solution (Stage 1:8 weeks) and, second, with regard to recovery once access to sucrose ceased (Stage 2:4 weeks).

Pre-Exposure, But Not Overshadowing, Inhibits Nocebo Hyperalgesia.

Nocebo hyperalgesia is a pervasive problem that significantly adds to the burden of pain. Conditioning is a key mechanism of nocebo hyperalgesia and recent evidence indicates that, once established, nocebo hyperalgesia is resistant to extinction. This means that preventive strategies are critical.

Sugar consumption and behavioural inhibition in the rat.

The metabolic effects of sugary drinks have been extensively studied, whereas the effects on psychological processes have received relatively limited attention. Several studies have found that high-sugar diets can produce impaired performance by rats on tests assessing spatial learning and memory. In contrast, despite claims that weakened inhibitory control underlies many sugar-induced deficits, evidence supporting this proposal has been limited.

Comparable metabolic effects of isocaloric sucrose and glucose solutions in rats.

Much of the global increase in sugar intake is attributable to rising consumption of sugar-sweetened beverages (SSBs). Because people compensate poorly for liquid calories, SSB consumption increases total energy intake, raising the risk of harmful metabolic effects in addition to possible effects of sugars per se. Glucose and fructose, the constituent sugars in sucrose, can exert distinct effects on metabolism and also differ in their satiating properties, suggesting that compensation for the calories in these sugars may also vary.

Metabolic and behavioural effects in offspring exposed to maternal sucrose consumption: a systematic review and meta-analysis of data from rodent models.

Consumption of sugar-sweetened beverages (SSBs) during pregnancy has been associated with childhood obesity. Research in which rodent dams have been given high-fat/high-sugar diets has consistently found metabolic alterations in their offspring. However, what remains unclear is the potential impact on the developing fetus of giving sugar in isolation at concentrations similar to SSBs to the mothers.

Time-of-day affects the amount rats run during daily sessions in activity wheels.

When rats are given daily sessions of access to activity wheels, the amount that they run can increase over sessions. In addition to the suggestion that this could indicate the development of an addiction, there are alternative explanations. The present study tested whether running at a fixed time of day (ToD) might allow stronger entrainment of circadian rhythms than running at varied ToDs.

Reduced acceptance of saccharin solutions by rats previously consuming more highly palatable solutions.

Rats first given 24-h access to 10% sucrose for 4 or 12 days (Stage 1) were then switched to a saccharin solution for a 12-day Stage 2. The initial result of this switch was that these Sucrose groups drank less saccharin than Water groups that had been given only water to drink in Stage 1. This difference was maintained throughout Stage 2 by the females that served in Experiments 1 and 4 and by the males that served in Experiment 3.

Metabolic and behavioural effects of prenatal exposure to non-nutritive sweeteners: A systematic review and meta-analysis of rodent models.

Little is known about possible effects of maternal non-nutritive sweetener (NNS) consumption on the metabolic health of a child. Animal models of maternal NNS consumption during pregnancy or weaning have yielded widely varying results, and there appears to be no clear consensus on the consequences for offspring body weight, glycaemic control or sweet preference choices. Moreover, heterogeneity in study design has hampered a clear focus for future research relevant to human health.

Bingeing in rats: Persistence of high intakes of palatable solutions induced by 1-day-in-4 intermittent access.

When animals are given access to a palatable food or drink on some days but not on others, the amount they consume can far exceed the daily amounts consumed by controls given daily access. A previous study demonstrated such bingeing when rats were given 4% sucrose solution. Importantly, it also found that, following 1-day-in-4 access for many weeks, intakes remained persistently higher than that of controls even when the conditions were changed to 1-day-in-2 access for both groups.

The effect of dose expectancies on caffeine withdrawal symptoms during tapered dose reduction.

Background: Negative expectancies can exacerbate withdrawal symptoms via the nocebo effect. As such, information provided about dose reductions during attempts to taper a drug could contribute to withdrawal symptoms and increase the likelihood of relapse. The current study tested whether blinding participants to dose reductions during a supervised caffeine dose taper reduced these nocebo-induced withdrawal symptoms.

Sodium saccharin can be more acceptable to rats than pure saccharin.

The artificial sweetener saccharin is available in several forms, including pure saccharin (S) and saccharin sodium salt hydrate (SSSH). Acceptance and preference relative to 2% sucrose for these two forms was assessed using both older female and young male rats. At the higher of two concentrations, ∼0.

Motivation to run measured by progressive ratio tests: Failure to support the addiction hypothesis for rats.

When laboratory rats are given repeated access to an activity wheel, the amount that they run steadily increases. This suggests an analogy with drug dependency in animals and humans, in that this is marked by both increasing intakes of the drug and increasing motivation to obtain the drug (craving). This analogy was examined by measuring motivation to obtain an opportunity to run using a progressive ratio (PR) schedule, whereby the number of lever presses required to release a brake on an activity wheel was increased progressively.

Metabolic and cognitive improvement from switching to saccharin or water following chronic consumption by female rats of 10% sucrose solution.

High consumption of sugar-sweetened beverages (SSBs) is a risk factor for weight gain and metabolic disease. Whether this risk is reduced by switching to 'diet' beverages containing low-calorie sweeteners (LCS) is controversial. Two experiments modeled whether a switch from SSB to LCS beverages produced positive outcomes on behavioral and metabolic measures.

Variety overcomes the specificity of cue-potentiated feeding in rats.

Cue-potentiated feeding (CPF) describes the stimulation of food consumption by cues that have become associated with food. Determining under what Conditions CPF occurs is important to better understand how exposure to food cues contributes to overeating. CPF is typically found to be specific: cues enhance consumption only of the food they have signaled.

Situational relevance: Context as a factor in serial overshadowing of taste aversion learning.

In a serial overshadowing procedure, a target stimulus, A, is followed after an interval by a potentially interfering stimulus, B, and this is then followed by an unconditioned stimulus (US). An untested proposal from over four decades ago was that the degree to which B overshadows conditioning of A depends on whether or not the two events take place in the same context. To test this, two experiments used a 1-trial long-delay conditioned taste aversion (CTA) procedure: sucrose served as the target taste (A) and dilute hydrochloric acid (HCl) as the overshadowing taste (B), with lithium chloride injection providing the US.