Discover the most talked about and latest scientific content & concepts.

Journal: Physiology & behavior


Classical music has been shown to reduce stress in kennelled dogs; however, rapid habituation of dogs to this form of auditory enrichment has also been demonstrated. The current study investigated the physiological and behavioural response of kennelled dogs (n=38) to medium-term (5days) auditory enrichment with five different genres of music including Soft Rock, Motown, Pop, Reggae and Classical, to determine whether increasing the variety of auditory stimulation reduces the level of habituation to auditory enrichment. Dogs were found to spend significantly more time lying and significantly less time standing when music was played, regardless of genre. There was no observable effect of music on barking, however, dogs were significantly (z=2.2, P<0.05) more likely to bark following cessation of auditory enrichment. Heart Rate Variability (HRV) was significantly higher, indicative of decreased stress, when dogs were played Soft Rock and Reggae, with a lesser effect observed when Motown, Pop and Classical genres were played. Relative to the silent period prior to auditory enrichment, urinary cortisol:creatanine (UCCR) valueswere significantly higher during Soft Rock (t=2.781, P<0.01) and the second silent control period following auditory enrichment (t=2.46, P<0.05). Despite the mixed response to different genres, the physiological and behavioural changes observed remained constant over the 5d of enrichment suggesting that the effect of habituation may be reduced by increasing the variety of auditory enrichment provided.

Concepts: Time, Rock music, Opera, Genre, Musical notation, Blues, Music genre, Jazz


Food tastes better and people eat more of it when eaten with company than alone. Although several explanations have been proposed for this social facilitation of eating, they share the basic assumption that this phenomenon is achieved by the existence of co-eating others. Here, we demonstrate a similar “social” facilitation of eating in the absence of other individuals. Elderly participants tasted a piece of popcorn alone while in front of a mirror (which reflects the participant themselves eating popcorn) or in front of a wall-reflecting monitor, and were found to eat more popcorn and rate it better tasting in the self-reflecting condition than in the monitor condition. Similar results were found for younger adults. The results suggest that the social facilitation of eating does not necessarily require the presence of another individual. Furthermore, we observed a similar “social” facilitation of eating even when participants ate a piece of popcorn in front of a static picture of themselves eating, suggesting that static visual information of “someone” eating food is sufficient to produce the “social” facilitation of eating.

Concepts: Nutrition, Participation, Eating, Food, Observation, Philosophy of science, Taste, Food and drink


Oxidative damage is one of the hallmarks of the aging process. The current study evaluated effects of two proprietary antioxidant-based ingredients, rosemary extract and spearmint extract containing carnosic acid and rosmarinic acid, respectively, on learning and memory in the SAMP8 mouse model of accelerated aging.The two rosemary extracts contained carnosic acid (60% or 10% carnosic acid) and one spearmint extract contained 5% rosmarinic acid. Three doses of actives in each extract were tested: 32, 16, 1.6 or 0mg/kg. After 90days of treatment mice were tested in T-maze foot shock avoidance, object recognition and lever press. Rosemary extract containing 60% carnosic acid improved acquisition and retention in T-maze foot shock, object recognition and lever press. Rosemary extract with 10% carnosic acid improved retention in T-maze foot shock avoidance and lever press. Spearmint with 5% rosmarinic acid improved acquisition and retention in T-maze foot shock avoidance and object recognition. 4-hydroxynonenal (HNE) was reduced in the brain cortex after treatment with all three extracts (P<0.001) compared to the vehicle treated SAMP8. Protein carbonyls were reduced in the hippocampus after administration of rosemary with 10% carnosic acid (P<0.05) and spearmint containing 5% rosmarinic acid (P<0.001). The current results indicate that the extracts from spearmint and rosemary have beneficial effects on learning and memory and brain tissue markers of oxidation that occur with age in SAMP8 mice.

Concepts: Carbon dioxide, Brain, Redox, Human brain, Cerebral cortex, Hippocampus, Carbonyl, Rosemary


To conduct a systematic review of the effects of chewing on appetite, food intake and gut hormones, and a meta-analysis of the effects of chewing on self-reported hunger.

Concepts: Eating, Food and drink


The aim of the present study was to examine the effect of mild hypohydration on performance during a prolonged, monotonous driving task.

Concepts: Present, Time, Driver's license


The idea that food intake is motivated by (or in anticipation of) ‘hunger’ arising from energy depletion is apparent in both public and scientific discourse on eating behaviour. In contrast, our thesis is that eating is largely unrelated to short-term energy depletion. Energy requirements meal-to-meal are trivial compared with total body energy stores, so energy supply to the body’s tissues is maintained if a meal or even several meals are missed. Complex and exquisite metabolic machinery ensures that this happens, but metabolic regulation is only loosely coupled with the control of energy intake. Instead, food intake needs to be controlled because the limited capacity of the gut means that processing a meal presents a significant physiological challenge and potentially hinders other activities. We illustrate the relationship between energy (food) intake and energy expenditure with a simple analogy in which: (1) water in a bathtub represents body energy content, (2) water in a saucepan represents food in the gut, and (3) the bathtub is filled via the saucepan. Furthermore, (4) it takes hours to process and pass the full energy (macronutrient) content of the saucepan to the bathtub, and (5) both the saucepan and bathtub resist overfilling, representing negative feedbacks on appetite (desire to eat). This model is consistent with the observations that appetite is reduced acutely by energy intake (a meal added to the limited capacity of the saucepan/gut), but not by an increase in acute energy expenditure (energy removed from the large store of energy in the bathtub/body). The existence of a relatively weak but chronic negative feedback effect on appetite proportional to body fatness is supported by observations on the dynamics of energy intake and weight gain in rat dietary obesity. (We use the term ‘appetite’ here because ‘hunger’ implies energy depletion.) In our model, appetite is motivated by the accessibility of food and the anticipated and experienced pleasure of eating it. The latter, which is similar to food reward, is determined primarily by the state of the emptiness of the gut and food liking related to the food’s sensory qualities and macronutrient value and the individual’s dietary history. Importantly, energy density adds value because energy dense foods are less satiating kJ for kJ and satiation limits further intake. That is, energy dense foods promote energy intake by virtue (1) of being more attractive and (2) having low satiating capacity kJ for kJ, and (1) is partly a consequence of (2). Energy storage is adapted to feast and famine and that includes unevenness over time of the costs of obtaining and ingesting food compared with engaging in other activities. However, in very low-cost food environments with energy dense foods readily available, risk of obesity is high. This risk can be and is mitigated by dietary restraint, which in its simplest form could mean missing the occasional meal. Another strategy we discuss is the energy dilution achieved by replacing some sugar in the diet with low-calorie sweeteners. Perhaps as or more significant, though, is that belief in short-term energy balancing (the energy depletion model) may undermine attempts to eat less. Therefore, correcting narratives of eating to be consistent with biological reality could also assist with weight control.

Concepts: Nutrition, Energy, Obesity, Eating, Food, Appetite, Energy density, Food and drink


Purified high-fat diet (HFD) feeding causes deleterious metabolic and cognitive effects when compared with unrefined low-fat diets in rodent models. These effects are often attributed to the diet’s high content of fat, while less attention has been paid to other mechanisms associated with the diet’s highly refined state. Although the effects of HFD feeding on cognition have been explored, little is known about the impact of refined vs. unrefined food on cognition. We tested the hypothesis that a refined low-fat diet (LFD) increases body weight and adversely affects cognition relative to an unrefined diet.

Concepts: Psychology, Nutrition, Obesity, Cognitive psychology, Fat, Cognition, Educational psychology, Dieting


Grocery stores represent a context in which a majority of people’s food purchases occur. Considering the nutrition quality of the population’s food intake has dramatically decreased, understanding how to improve food choice in the grocery store is paramount to healthier living. In this work, we detail the type of financial resources from which shoppers could draw (i.e., personal income and benefits from government food assistance programs to low income populations) and explain how these financial resources are allocated in the grocery store (i.e., planned, unplanned, error). Subsequently, we identify a conceptual framework for shopper marketing nutrition interventions that targets unplanned fruit and vegetable purchases (i.e., slack, or willingness to spend minus list items). Targeting slack for fresh fruit and vegetable purchases allows retailers to benefit economically (i.e., fruit and vegetables are higher margin) and allows shoppers to improve their nutrition without increasing their budgets (i.e., budget neutrality). We also provide preliminary evidence of what in-store marketing of fresh fruits and vegetables could entail by modifying grocery carts and grocery floors to provide information of what is common, normal, or appropriate fruit and vegetable purchases. In each example, fresh fruit and vegetable purchases increased and evidence suggested shopper budget neutrality. To provide context for these results, we detail measurement tools that can be used to measure shopper behaviors, purchases, and consumption patterns. Finally, we address theoretical, practical, and policy implications of shopper marketing nutrition interventions.

Concepts: Nutrition, Fruit, Tomato, Vegetable, Vegetarian cuisine, Supermarket, Grocery store, Grocer


Harmane (HA) is a β-carboline alkaloid derived from the Peganum harmala plant which induces memory impairment. On the other hand some of the investigations showed that β-carboline alkaloids inhibit NO production. Thus, the aim of the present study was to investigate the role of nitrergic system of the dorsal hippocampus (CA1) in HA-induced amnesia in male adult mice. One-trial step-down passive avoidance and hole-board apparatuses were used for the assessment of memory retrieval and exploratory behaviors respectively. The data indicated that pre-training intraperitoneal (i.p.) administration of HA (12 and 16mg/kg) decreased memory acquisition. Sole pre-training or pre-testing administration of L-NAME, a nitric oxide synthesis inhibitor (5, 10 and 15μg/mice, intra-CA1) did not alter memory retrieval. On the other hand, pre-training (10 and 15μg/mice, intra-CA1) and pre-testing (5, 10μg/mice, intra-CA1) injections of L-NAME restored HA-induced amnesia (16mg/kg, i.p.). Furthermore, neither sole pre-training nor pre-testing administration of l-arginine, a NO precursor (3, 6 and 9μg/mice, intra-CA1), altered memory retrieval. In addition, pre-testing (6 and 9μg/mice, intra-CA1), but not pre-training, injection of l-arginine increased HA-induced amnesia (16mg/kg, i.p.). These results suggest that the nitrergic system of CA1 is involved in HA-induced amnesia.

Concepts: Nitrogen, Hippocampus, Nitric oxide, Amnesia, Alkaloid, Harmal, Harmala alkaloid, Harmine


Laboratory rats display pronounced defensive behaviors when confronted with a range of cat-derived stimuli, including collars worn by a cat, cloths rubbed on a cat, and cat fur. One possible explanation of this phenomenon (the “kairomone hypothesis”) is that rats derive a survival advantage by eavesdropping on signals used by cats to communicate with each other. Cats are known to rub their bodies on objects at strategic environmental locations to signal their identity and mating potential to other cats. The current study assessed the sensitivity of laboratory rats to these body rubbings. In Experiment 1, food deprived Sprague-Dawley rats were trained to consume food pellets in one arm of a Y maze. On test day a damp cloth was placed near the food pellets that had been rubbed on a location (wall) where a cat had recently engaged in body rubbing. A control cloth and a collar worn by the cat were also tested. The presence of both the body rubbing residue and the cat collar increased latency to eat and decreased amount of food eaten. The disruption of consummatory behavior in the test environment was still evident 24h later in the absence of odor stimuli. Experiment 2 tested the reaction of naïve Wistar rats to body rubbings using a paradigm in which rats were given the opportunity to hide. Relative to a control condition, rats exposed to a cotton pad wiped on a cat body rubbing location showed increased hiding behavior, decreased exploration and reduced stimulus approach and investigation. These defensive responses persisted for up to 4days following a single stimulus exposure. These results suggest that rats eavesdrop readily on body rubbings cats use for identification purposes, providing further support for a kairomone hypothesis of predator odor avoidance.

Concepts: Predation, Rat, Cat, Toxoplasmosis, Laboratory rat, Rubbing, Cat coat genetics, Fur