The Interaction between Discriminative Stimuli and Outcomes during Instrumental Learning

2003 ◽  
Vol 56 (1b) ◽  
pp. 127-139 ◽  
Author(s):  
Anthony Dickinson ◽  
Sanne de Wit
Keyword(s):  
Sucrose Solution ◽  
Food Pellet ◽  
Instrumental Learning ◽  
The Other ◽  
Food Type ◽  
Instrumental Performance ◽  
Stimulus Function ◽  
Associative Structures ◽  
Congruent Group ◽  
Biconditional Discrimination

Rats were trained on a biconditional discrimination in which the delivery of a food pellet stimulus signalled that pressing on one of two levers would be reinforced, whereas the delivery of a sucrose solution stimulus signalled that the reward was contingent on pressing the other lever. The outcome was the same food type as the discriminative stimulus in the congruent group but the other food type in the incongruent group. Both responses were rewarded with the same outcome in the same group. All the three groups learned the discrimination at statistically indistinguishable rates. Prefeeding one of the outcomes selectively reduced the associated response thereby demonstrating that responding was mediated by a representation of the outcome. Moreover, the outcome of one trial controlled responding on the next trial in accord with the stimulus function of the food type. These results are discussed in relation to the associative structures mediating the discriminative control of instrumental performance.

Discrimination between Outcomes in Instrumental Learning: Effects of Preexposure to the Reinforcers

2003 ◽  
Vol 56 (3b) ◽  
pp. 253-265 ◽  
Author(s):  
C.A.J. Blair ◽  
Pam Blundell ◽  
Tiffany Galtress ◽  
Geoffrey Hall ◽  
Simon Killcross
Keyword(s):  
Perceptual Learning ◽  
Learning Effect ◽  
Sucrose Solution ◽  
Instrumental Learning ◽  
Test Session ◽  
The Other ◽  
Free Access ◽  
Learning Effects ◽  
Instrumental Training ◽  
Mixed Schedule

In two experiments rats received instrumental training with two response levers, one response being reinforced by sucrose solution and the other by sucrose pellets. Prior to a test session, on which both levers were made available in the absence of reinforcement, the rats were given free access to one of the reinforcers, a procedure known to reduce its value. It was found that the rats responded at a lower rate on the lever that had produced the now-devalued reinforcer, but that this effect was substantial only in rats that had received preexposure to the two reinforcers before instrumental training was begun (Experiment 1). Experiment 2 demonstrated that this effect was obtained only when presentations of the two reinforcers were presented according to an inter-mixed schedule during preexposure. It is suggested that this result constitutes an instance of the perceptual learning effect in which intermixed preexposure to similar events enhances their discriminability.

Beyond the Reward Pathway: Coding Reward Magnitude and Error in the Rat Subthalamic Nucleus

2009 ◽  
Vol 102 (4) ◽  
pp. 2526-2537 ◽  
Author(s):  
Sylvie Lardeux ◽  
Remy Pernaud ◽  
Dany Paleressompoulle ◽  
Christelle Baunez
Keyword(s):  
Subthalamic Nucleus ◽  
Firing Pattern ◽  
Sucrose Solution ◽  
Critical Role ◽  
The Other ◽  
Reward Circuitry ◽  
Reward Delivery ◽  
Reward Pathway ◽  
Subthalamic Neurons ◽  
The Brain

It was recently shown that subthalamic nucleus (STN) lesions affect motivation for food, cocaine, and alcohol, differentially, according to either the nature of the reward or the preference for it. The STN may thus code a reward according to its value. Here, we investigated how the firing of subthalamic neurons is modulated during expectation of a predicted reward between two possibilities (4 or 32% sucrose solution). The firing pattern of neurons responding to predictive cues and to reward delivery indicates that STN neurons can be divided into subpopulations responding specifically to one reward and less or giving no response to the other. In addition, some neurons (“oops” neurons) specifically encode errors as they respond only during error trials. These results reveal that the STN plays a critical role in ascertaining the value of the reward and seems to encode that value differently depending on the magnitude of the reward. These data highlight the importance of the STN in the reward circuitry of the brain.

scholarly journals Composition of dental plaque formed in the presence of sucrose and after its interruption

2003 ◽  
Vol 14 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Jaime Aparecido Cury ◽  
Aline Soler Marques ◽  
Cíntia Pereira Machado Tabchoury ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Crossover Study ◽  
Dental Plaque ◽  
Sucrose Solution ◽  
Inorganic Phosphorus ◽  
Deionized Water ◽  
The Other ◽  
Low Concentration ◽  
Human Enamel ◽  
Two Stages

Since dental plaque reservoirs of fluoride (F), calcium (Ca) and inorganic phosphorus (Pi) are susceptible to decreases in pH, this in situ crossover study was conducted to test the hypothesis that the low concentration of these ions in plaque, formed in the presence of sucrose, could be attributed merely to the fermentation of this sugar. Eleven volunteers wore palatal appliances containing 6 human enamel blocks during two stages. In each stage, the treatments were either 20% sucrose solution or distilled deionized water, which were dripped onto the blocks 8 times a day. After 28 days, in each stage, the dental plaque formed on two blocks was collected, the treatment was inverted and after a further 24 and 48 h, the biofilm formed was collected from the other blocks. The concentration of acid-soluble F, Ca and Pi, and the concentration of insoluble polysaccharide (IP) were determined in the dental plaque. Statistically lower concentrations of F, Ca and Pi, and a higher concentration of IP were found in the 28-day biofilm formed in the presence of sucrose than in its absence; after the treatment inversion the change in F, Ca and Pi was not statistically significant, but the IP concentration changed significantly. The hypothesis was rejected because change in concentration of F, Ca and Pi is not due to fermentation of the sucrose.

Regulatory alterations of daily energy expenditure induced by fasting or overfeeding in unrestrained rats

1987 ◽  
Vol 63 (2) ◽  
pp. 465-470 ◽  
Author(s):  
H. Shibata ◽  
L. J. Bukowiecki
Keyword(s):  
Energy Expenditure ◽  
Energy Intake ◽  
Normal Values ◽  
Sucrose Solution ◽  
Normal Diet ◽  
The Other ◽  
O2 Consumption ◽  
Daily Energy Expenditure ◽  
Daily Energy ◽  
Ad Libitum

The consequences of fasting or overfeeding during 2 days on energy expenditure were investigated by continuously monitoring O2 consumption in unrestrained, unanesthetized rats. O2 consumption decreased by 15% on the 1st day of fasting and then by an additional 15% on the 2nd day. On the 3rd day, when rats were fed again, energy intake increased by 30% above control (prefasting) values, whereas energy expenditure rapidly increased but no more than control values. On the other hand, when ad libitum fed animals were offered a sucrose solution (32%) for 2 days, energy intake increased by 30% and energy expenditure by 9–12%. On the 3rd day, when the rats were fed with their normal diet, energy intake significantly decreased under control (preoverfeeding) values during one day, but energy expenditure rapidly returned to normal values. The results show that fasting decreases, whereas hyperphagia increases 24-h energy expenditure during the treatments. When the treatments are terminated, energy expenditure rapidly returns to normal values, but fasting induces a postfasting increase of energy intake (during 2 days), whereas hyperphagia, on the contrary, results in a transient decrease of appetite. This indicates that alterations of food intake induce compensatory changes of energy expenditure during the treatments, but that after the treatments, energy balance is normalized via regulatory adjustments in the ratio of energy expenditure over energy intake.

scholarly journals Prevalence of and risk factors for feline hyperthyroidism in Hong Kong

2009 ◽  
Vol 11 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Cornelia S. De Wet ◽  
Carmel T. Mooney ◽  
Peter N. Thompson ◽  
Johan P. Schoeman
Keyword(s):  
Risk Factors ◽  
Hong Kong ◽  
Potential Risk ◽  
The Other ◽  
Food Type ◽  
Significant Difference ◽  
The World ◽  
Total Thyroxine ◽  
Potential Risk Factors ◽  
Specific Association

A study was conducted to determine the prevalence of and potential risk factors for feline hyperthyroidism in Hong Kong. Serum total thyroxine (T4) was measured in 305 cats aged 10 years and older that presented at various veterinary clinics in Hong Kong. The prevalence of hyperthyroidism (T4>50 nmol/l) within this population was 3.93% and there was no significant difference in prevalence between healthy (3.16%) and sick (4.37%) cats. Older cats (>15 years) were more likely to be affected and domestic shorthair cats were less likely to be diagnosed with hyperthyroidism than the other breeds combined. No specific association between the development of feline hyperthyroidism and food type was observed. The prevalence of feline hyperthyroidism in Hong Kong was less than that reported for most other parts of the world, despite the presence of previously identified risk factors.

scholarly journals CYTOKININ DIPS AND SUCROSE HOLDING SOLUTIONS INCREASE THE POSTHARVEST LONGEVITY OF `NITTA' ANTHURIUMS AND PINK GINGERS.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 617b-617
Author(s):  
Jane Whittaker ◽  
Terril A. Nell ◽  
James E. Barrett ◽  
Thomas J. Sheehan
Keyword(s):  
Sucrose Solution ◽  
The Other ◽  
Postharvest Longevity ◽  
Alpinia Purpurata

The effect of postharvest dips on the longevity of Anthurium andraenum cultivar Nitta and Alpinia purpurata was evaluated. The inflorescences were dipped in a 200 ppm benzyladenine (BA) solution, an antitranspirant, or water for 10 minutes. After dipping, anthuriums were placed directly in water and gingers were placed in either water or a 2% sucrose solution and placed in interior conditions (10 μmol m-2s-1 for 12 hr/day, 21±2C). Ginger longevity was increased by 10 days or more by the sucrose solution. The greatest longevity of gingers was obtained when dipped in either BA or the antitranspirant and held in the sucrose solution. Anthurium longevity increased 10 days when dipped in BA, while the other treatments had little effect.

scholarly journals Reinforcer Quality and Self-Control

2021 ◽  
Author(s):  
◽  
Heather L Peters
Keyword(s):  
Sucrose Solution ◽  
Matching Law ◽  
Self Control ◽  
The Other ◽  
Terminal Link ◽  
Impulsive Choice ◽  
Initial Link ◽  
Scaling Parameter ◽  
Control Paradigm ◽  
Reinforcer Quality

<p>Self-control has been extensively studied using procedures in which subjects chose between two reinforcer alternatives. Traditionally, one of those alternatives delivers a small reinforcer after a short delay (SI), the other, a larger reinforcer after a long delay (LD). Choosing the SI is defined as impulsivity as it requires forfeit of the larger reinforcer; and choosing the LD is termed self-control. Four experiments were conducted to examine behaviour using non-human animal analogues of self-control situations. The subjects used for all four experiments were Norway-hooded rats. Experiment 1 used an SI - LD self-control paradigm to examine the effect of manipulating reinforcer quality on response distribution. Findings were that behaviour became more impulsive as the delay ratio became more extreme and this tendency was more systematic when different quality reinforcers were used for the SI and LD alternatives. Experiments 2 and 3 introduced a novel self-control paradigm designed as an analogue of choice situations in which individuals choose between two competing immediately available reinforcers each associated with a different delayed reinforcer. The procedure used was a concurrent-chains schedule that delivered primary reinforcement in the initial and the terminal links. The initial reinforcers were of equal amount and unequal quality; the terminal reinforcers were of unequal amount and equal quality. An impulsive choice was defined as choosing the alternative that delivered the most-valuable reinforcer in the initial link and the least-valued reinforcer in the terminal link. A self-controlled choice was defined as choosing the alternative that delivered the least-valuable reinforcer in the initial link and the most-valuable reinforcer in the terminal link. The results indicated that behaviour was more self-controlled when the terminal reinforcer quality was ethanol solution and increasing the delay between the initial and terminal links increased subjects' responding on the impulsive choice. Behaviour allocation in Experiment 3 was well described by the Contextual Choice Model (Grace, 1994) when the temporal context scaling parameter (k) was allowed to vary. Subjects that were relatively more impulsive had lower derived k values. The final experiment presented the subjects from Experiment 3 with concurrent variable interval (VI) VI schedules in which one alternative delivered plain-sucrose solution and the other ethanol-sucrose solution. Preference measures obtained from Experiment 4 were negatively correlated with the values obtained for the scaling parameter in Experiment 3, indicating that subjects which were more impulsive in the MN - ML paradigm had a stronger preference for ethanol. In summary, findings indicate that reinforcer quality may change the discriminability of reinforcer alternatives; and the influence of reinforcer quality on response allocation is well described by quantitative models based on the Matching Law.</p>

scholarly journals Research Regarding the Sensorial Profile Characterization on Lamb Meat

2012 ◽  
Vol 69 (2) ◽  
Author(s):  
Otilia Cristina CRÄ‚CIUN (MURARIU) ◽  
Florin MURARIU ◽  
Paul Corneliu BOI ȘTEANU
Keyword(s):  
Quality Improvement ◽  
Production System ◽  
The Other ◽  
Food Type ◽  
Consumer Expectations ◽  
Lamb Meat ◽  
Productive System ◽  
Different Types

The main goal of this study was to evaluate the consumer expectations generated by the knowledge of food type provided to animals, to determine their effect on the hedonistic evaluation of Karakul breed lamb. Mean sensorial characteristics of different types of lamb were evaluated by a panel of trained tasters, who showed a clear perception of various meats gentleness, belonging to the same commercial category, produced by young sheep fed with milk (MM)/milk and concentrate (MC)/milk and forage (MF).Meat provided from lambs fed with milk and grass was considered tougher, more difficult to chew and more fibrous than that derived from MM and MC lambs. Productive system has also influenced some aspects of the aromatic profile of lamb meat, due to diversified food. The young sheep produced a meat flavour characterized more persistent than the other two groups of lambs. However, MM lamb led to a greater perception of taste metallic/blood, that the other two groups. We consider that is very important to introduce the criteria of production system to obtaining lamb meat on the labels, because it can generate positive consumer expectations and perceptions on quality improvement before tasting meat.

scholarly journals Ultrasound-Assisted Osmotic Dehydration of Apples in Polyols and Dihydroxyacetone (DHA) Solutions

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3429 ◽  
Author(s):  
Joanna Cichowska ◽  
Dorota Witrowa-Rajchert ◽  
Lidia Stasiak-Różańska ◽  
Adam Figiel
Keyword(s):  
Water Activity ◽  
Sucrose Solution ◽  
Osmotic Dehydration ◽  
Continuous Method ◽  
The Other ◽  
Water Removal ◽  
Colour Changes ◽  
Apple Tissue ◽  
Transfer Parameters ◽  
Ultrasound Assisted

The aim of this work was to analyse the effect of ultrasound-assisted osmotic dehydration of apples v. Elise on mass transfer parameters, water activity, and colour changes. Ultrasound treatment was performed at a frequency of 21 kHz with a temperature of 40 °C for 30–180 min using four osmotic solutions: 30% concentrated syrups of erythritol, xylitol, maltitol, and dihydroxyacetone (DHA). The efficiency of the used solutes from the polyol groups was compared to reference dehydration in 50% concentrated sucrose solution. Peleg’s model was used to fit experimental data. Erythritol, xylitol, and DHA solutions showed similar efficiency to sucrose and good water removal properties in compared values of true water loss. The application of ultrasound by two methods was in most cases unnoticeable and weaker than was expected. On the other hand, sonication by the continuous method allowed for a significant reduction in water activity in apple tissue in all tested solutions.

Effects of Vanadium Inhalation and Sweetened Beverage Ingestion in Mice: Morphological and Biochemical Changes in the Liver

2021 ◽  
pp. 109158182110308
Author(s):  
María Eugenia Cervantes-Valencia ◽  
Adriana González-Villalva ◽  
Gumaro Cano-Gutiérrez ◽  
Juan Carlos Albarrán-Alonso ◽  
Teresa Imelda Fortoul
Keyword(s):  
Oxidative Stress ◽  
Sucrose Solution ◽  
Liver Function Tests ◽  
Biochemical Changes ◽  
The Other ◽  
Control Group ◽  
Sweetened Beverage ◽  
Sweetened Beverages ◽  
Group 4 ◽  
Group A

The aim of this report was to evaluate the morphological and biochemical changes in the liver by the inhalation of vanadium and consumption of sweetened beverages in a subchronic murine model. Forty CD-1 male mice were randomly divided into four groups: control, vanadium (V), sucrose 30% (S), and vanadium–sucrose (V + S). V was inhaled (1.4 mg/m3) for 1h, twice/week; 30% sucrose solution was given orally ad libitum. Blood samples were obtained for AST, ALT, and LDH determination. Liver samples were processed for histological and oxidative stress immunohistochemical evaluation with 4-hydroxynonenal at weeks 4 and 8 of exposure. Regarding liver function tests, a statistically significant increase ( P < 0.05) was observed in groups V, S, and V + S at weeks 4 and 8 compared to the control group. A greater number of hepatocytes with meganuclei and binuclei were observed in V and V + S at week 8 compared to the other groups. Steatosis and regenerative changes were more extensive in the eighth week V + S group. 4-Hydroxynonenal immunoreactivity increased in the V + S group at both exposure times compared to the other groups; however, the increment was more evident in the V + S group at week 4 compared to the V + S group at week 8. An increase in De Ritis ratio (>1) was noticed in experimental groups at weeks 4 and 8. Findings demonstrate that in the liver, V, S, and V + S induced oxidative stress and regenerative changes that increased with the length of exposure. Results support possible potentiation of liver damage in areas with high air pollution and high-sweetened beverage consumption.

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