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Hernandez CM, Vetere LM, Orsini CA, McQuail JA, Maurer AP, Burke SN, Setlow B, Bizon JL. Decline of prefrontal cortical-mediated executive functions but attenuated delay discounting in aged Fischer 344 × brown Norway hybrid rats. Neurobiol Aging 2017; 60:141-152. [PMID: 28946018 DOI: 10.1016/j.neurobiolaging.2017.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/24/2017] [Accepted: 08/25/2017] [Indexed: 11/18/2022]
Abstract
Despite the fact that prefrontal cortex (PFC) function declines with age, aged individuals generally show an enhanced ability to delay gratification, as evident by less discounting of delayed rewards in intertemporal choice tasks. The present study was designed to evaluate relationships between 2 aspects of PFC-dependent cognition (working memory and cognitive flexibility) and intertemporal choice in young (6 months) and aged (24 months) Fischer 344 × brown Norway F1 hybrid rats. Rats were also evaluated for motivation to earn rewards using a progressive ratio task. As previously reported, aged rats showed attenuated discounting of delayed rewards, impaired working memory, and impaired cognitive flexibility compared with young. Among aged rats, greater choice of delayed reward was associated with preserved working memory, impaired cognitive flexibility, and less motivation to work for food. These relationships suggest that age-related changes in PFC and incentive motivation contribute to variance in intertemporal choice within the aged population. Cognitive impairments mediated by PFC are unlikely, however, to fully account for the enhanced ability to delay gratification that accompanies aging.
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Affiliation(s)
| | - Lauren M Vetere
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Caitlin A Orsini
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Joseph A McQuail
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Andrew P Maurer
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Sara N Burke
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Barry Setlow
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA.
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Taste preference changes throughout different life stages in male rats. PLoS One 2017; 12:e0181650. [PMID: 28742813 PMCID: PMC5526549 DOI: 10.1371/journal.pone.0181650] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/30/2017] [Indexed: 11/19/2022] Open
Abstract
Taste preference, a key component of food choice, changes with aging. However, it remains unclear how this occurs. To determine differences in taste preference between rats in different life stages, we examined the consumption of taste solutions and water using a two-bottle test. Male Sprague-Dawley rats of different ages were used: juvenile (3-6 weeks), young adult (8-11 weeks), adult (17-20 weeks), middle-aged (34-37 weeks), and old-aged (69-72 weeks). The intakes of the high and low concentration solutions presented simultaneously were measured. We observed that the old-aged group had lower preference ratios for 0.3 M sucrose and 0.1 M MSG in comparison with other groups. The preference ratio for 0.03 mM QHCl was higher in the middle-aged group than in the three younger groups and higher in the old-aged group than the juvenile group. The taste preferences for HCl and NaCl did not significantly differ among the age groups. The old-aged group tended to prefer high concentrations of sucrose, QHCl, NaCl, and MSG to low concentrations, indicating age-related decline in taste sensitivity. We also aimed to investigate differences between life stages in the electrophysiological responses of the chorda tympani nerve, one of the peripheral gustatory nerves, to taste stimuli. The electrophysiological recordings showed that aging did not alter the function of the chorda tympani nerve. This study showed that aging induced alterations in taste preference. It is likely that these alterations are a result of functional changes in other peripheral taste nerves, the gastrointestinal system, or the central nervous system.
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Marshall AT, Liu AT, Murphy NP, Maidment NT, Ostlund SB. Sex-specific enhancement of palatability-driven feeding in adolescent rats. PLoS One 2017; 12:e0180907. [PMID: 28708901 PMCID: PMC5510835 DOI: 10.1371/journal.pone.0180907] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 06/22/2017] [Indexed: 11/24/2022] Open
Abstract
It has been hypothesized that brain development during adolescence perturbs reward processing in a way that may ultimately contribute to the risky decision making associated with this stage of life, particularly in young males. To investigate potential reward dysfunction during adolescence, Experiment 1 examined palatable fluid intake in rats as a function of age and sex. During a series of twice-weekly test sessions, non-food-deprived rats were given the opportunity to voluntarily consume a highly palatable sweetened condensed milk (SCM) solution. We found that adolescent male, but not female, rats exhibited a pronounced, transient increase in SCM intake (normalized by body weight) that was centered around puberty. Additionally, adult females consumed more SCM than adult males and adolescent females. Using a well-established analytical framework to parse the influences of reward palatability and satiety on the temporal structure of feeding behavior, we found that palatability-driven intake at the outset of the meal was significantly elevated in adolescent males, relative to the other groups. Furthermore, although we found that there were some group differences in the onset of satiety, they were unlikely to contribute to differences in intake. Experiment 2 confirmed that adolescent male rats exhibit elevated palatable fluid consumption, relative to adult males, even when a non-caloric saccharin solution was used as the taste stimulus, demonstrating that these results were unlikely to be related to age-related differences in metabolic need. These findings suggest that elevated palatable food intake during adolescence is sex specific and driven by a fundamental change in reward processing. As adolescent risk taking has been hypothesized as a potential result of hypersensitivity to and overvaluation of appetitive stimuli, individual differences in reward palatability may factor into individual differences in adolescent risky decision making.
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Affiliation(s)
- Andrew T. Marshall
- Department of Anesthesiology and Perioperative Care, Center for Addiction Neuroscience, University of California, Irvine, Irvine, California, United States of America
- * E-mail: (SBO); (ATM)
| | - Angela T. Liu
- Department of Anesthesiology and Perioperative Care, Center for Addiction Neuroscience, University of California, Irvine, Irvine, California, United States of America
| | - Niall P. Murphy
- Hatos Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Nigel T. Maidment
- Hatos Center, Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Sean B. Ostlund
- Department of Anesthesiology and Perioperative Care, Center for Addiction Neuroscience, University of California, Irvine, Irvine, California, United States of America
- * E-mail: (SBO); (ATM)
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Ricker JM, Hatch JD, Powers DD, Cromwell HC. Fractionating choice: A study on reward discrimination, preference, and relative valuation in the rat (Rattus norvegicus). ACTA ACUST UNITED AC 2016; 130:174-86. [PMID: 27078079 DOI: 10.1037/com0000034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Choice behavior combines discrimination between distinctive outcomes, preference for specific outcomes and relative valuation of comparable outcomes. Previous work has focused on 1 component (i.e., preference) disregarding other influential processes that might provide a more complete understanding. Animal models of choice have been explored primarily utilizing extensive training, limited freedom for multiple decisions and sparse behavioral measures constrained to a single phase of motivated action. The present study used a paradigm that combines different elements of previous methods with the goal to distinguish among components of choice and explore how well components match predictions based on risk-sensitive foraging strategies. In order to analyze discrimination and relative valuation, it was necessary to have an option that shifted and an option that remained constant. Shifting outcomes among weeks included a change in single-option outcome (0 to 1 to 2 pellets) or a change in mixed-option outcome (0 or 5 to 0 or 3 to 0 or 1 pellets). Constant outcomes among weeks were also mixed-option (0 or 3 pellets) or single-option (1 pellet). Shifting single-option outcomes among weeks led to better discrimination, more robust preference and significant incentive contrast effects for the alternative outcome. Shifting multioptions altered choice components and led to dissociations among discrimination, preference, and reduced contrast effects. During extinction, all components were impacted with the greatest deficits during the shifting mixed-option outcome sessions. Results suggest choice behavior can be optimized for 1 component but suboptimal for others depending upon the complexity of alterations in outcome value between options. (PsycINFO Database Record
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Affiliation(s)
- Joshua M Ricker
- J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University
| | - Justin D Hatch
- J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University
| | - Daniel D Powers
- J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University
| | - Howard Casey Cromwell
- J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University
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Differential expression of hypothalamic, metabolic and inflammatory genes in response to short-term calorie restriction in juvenile obese- and lean-prone JCR rats. Nutr Diabetes 2015; 5:e178. [PMID: 26302065 PMCID: PMC4558559 DOI: 10.1038/nutd.2015.28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/08/2015] [Accepted: 07/21/2015] [Indexed: 01/02/2023] Open
Abstract
Background: Childhood obesity is an important early predictor of adult obesity and associated comorbidities. Common forms of obesity are underpinned by both environmental and genetic factors. However, the rising prevalence of obesity in genetically stable populations strongly suggests that contemporary lifestyle is a premier factor to the disease. In pediatric population, the current treatment/prevention options for obesity are lifestyle interventions such as caloric restriction (CR) and increase physical activity. In obese individuals, CR improves many metabolic parameters in peripheral tissues. Little is known about the effect of CR on the hypothalamus. This study aimed to assess the effect of CR on hypothalamic metabolic gene expression of young obese- and lean-prone animals. Methods: Male juvenile JCR:LA-cp obese-prone rats were freely fed (Obese-FF) or pair fed (Obese-FR) to lean-prone, free-feeding animals (Lean-FF). A group of lean-prone rats (Lean-FR) were matched for relative average degree of CR to Obese-FR rats. Results: In free-feeding conditions, obese-prone rats consumed more energy than lean-prone rats (P<0.001) and showed greater increases in body weight, fat mass, plasma glucose, insulin and lipids (P<0.01). These metabolic differences were associated with alterations of feeding-related neuropeptides expression in the hypothalamus, as well as pro-inflammatory cytokines and oxidative stress markers. When submitted to the same degree of CR, the two genotypes responded differently; hypothalamic inflammatory and oxidative stress gene expression was improved in Obese-FR, while it was worsened in Lean-FR rats. Conclusions: We demonstrate in JCR rats that the metabolic and inflammatory response of the brain to CR is genotype dependent.
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Samson RD, Venkatesh A, Patel DH, Lipa P, Barnes CA. Enhanced performance of aged rats in contingency degradation and instrumental extinction tasks. Behav Neurosci 2014; 128:122-33. [PMID: 24773433 DOI: 10.1037/a0035986] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Normal aging in rats affects behavioral performance on a variety of associative learning tasks under Pavlovian conditions. There is little information, however, on whether aging also impacts performance of instrumental tasks. Young (9-12 months) and aged (24-27 months) Fisher 344 rats were trained to press distinct levers associated with either maltodextrin or sucrose. The rats in both age groups increased their lever press frequency at a similar rate, suggesting that the initial acquisition of this instrumental task is not affected by aging. Using a contingency degradation procedure, we then addressed whether aged rats could adapt their behavior to changes in action-outcome contingencies. We found that young and aged rats do adapt, but that a different schedule of reinforcement is necessary to optimize performance in each age group. Finally, we also addressed whether aged rats can extinguish a lever press action as well as young rats, using 2 40-min extinction sessions on consecutive days. While extinction profiles were similar in young and aged rats on the first day of training, aged rats were faster to extinguish their lever presses on the second day, in spite of their performance levels being similar at the beginning of the session. Together these data support the finding that acquisition of instrumental lever press behaviors is preserved in aged rats and suggest that they have a different threshold for switching strategies in response to changes in action-outcome associations. This pattern of result implies that age-related changes in the brain are heterogeneous and widespread across structures.
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Affiliation(s)
| | - Anu Venkatesh
- Evelyn F. McKnight Brain Institute, University of Arizona
| | - Dhara H Patel
- Evelyn F. McKnight Brain Institute, University of Arizona
| | - Peter Lipa
- Evelyn F. McKnight Brain Institute, University of Arizona
| | - Carol A Barnes
- Evelyn F. McKnight Brain Institute, University of Arizona
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Harb MR, Sousa N, Zihl J, Almeida OFX. Reward components of feeding behavior are preserved during mouse aging. Front Aging Neurosci 2014; 6:242. [PMID: 25278876 PMCID: PMC4165288 DOI: 10.3389/fnagi.2014.00242] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/25/2014] [Indexed: 01/10/2023] Open
Abstract
Eating behavior depends on associations between the sensory and energetic properties of foods. Healthful balance of these factors is a challenge for industrialized societies that have an abundance of food, food choices and food-related cues. Here, we were interested in whether appetitive conditioning changes as a function of age. Operant and pavlovian conditioning experiments (rewarding stimulus was a palatable food) in male mice (aged 3, 6, and 15 months) showed that implicit (non-declarative) memory remains intact during aging. Two other essential components of eating behavior, motivation and hedonic preference for rewarding foods, were also found not to be altered in aging mice. Specifically, hedonic responding by satiated mice to isocaloric foods of differing sensory properties (sucrose, milk) was similar in all age groups; importantly, however, this paradigm disclosed that older animals adjust their energy intake according to energetic need. Based on the assumption that the mechanisms that control feeding are conserved across species, it would appear that overeating and obesity in humans reflects a mismatch between ancient physiological mechanisms and today's cue-laden environment. The implication of the present results showing that aging does not impair the ability to learn stimulus-food associations is that the risk of overeating in response to food cues is maintained through to old age.
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Affiliation(s)
- Mazen R Harb
- Max Planck Institute of Psychiatry Munich, Germany ; Portugal and ICVS/3B's-PT Government Associate Laboratory, Institute of Life and Health Sciences (ICVS), University of Minho Braga, Portugal
| | - Nuno Sousa
- Portugal and ICVS/3B's-PT Government Associate Laboratory, Institute of Life and Health Sciences (ICVS), University of Minho Braga, Portugal
| | - Joseph Zihl
- Department of Neuropsychology, Ludwig Maximilian University Munich, Germany
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Sackmann-Sala L, Berryman DE, Lubbers ER, Vesel CB, Troike KM, List EO, Munn RD, Ikeno Y, Kopchick JJ. Decreased insulin sensitivity and increased oxidative damage in wasting adipose tissue depots of wild-type mice. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1225-37. [PMID: 21953241 PMCID: PMC3448990 DOI: 10.1007/s11357-011-9304-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 08/19/2011] [Indexed: 05/08/2023]
Abstract
Unintentional weight loss (wasting) in the elderly is a major health concern as it leads to increased mortality. Several studies have focused on muscle loss, but little is known about the mechanisms giving rise to loss of fat mass at old ages. To investigate potential mechanisms, white adipose tissue (WAT) characteristics and proteomic profiles were compared between adult (10-12-month-old) and aged (22-24-month-old) wild-type mice. Four individual WAT depots were analyzed to account for possible depot-specific differences. Proteomic profiles of WAT depots, along with body weights and compositions, plasma levels of insulin, leptin and adiponectin, insulin tolerance, adipocyte sizes, and products of oxidative damage in each WAT depot were determined. We found that lean mass remained constant while fat mass and insulin tolerance were decreased in old age, as were adipocyte sizes in the WAT depots. Proteomic results showed increased levels of enolase, pyruvate dehydrogenase E1β, NAD(+)-dependent isocitrate dehydrogenase α, and ATP synthase subunit β, and decreased levels of carbonic anhydrase 3 in WAT of aged mice. These data suggest increased aerobic glucose oxidation in wasting WAT, consistent with decreased insulin signaling. Also, Cu/Zn superoxide dismutase and two chaperones were increased in aged WAT depots, indicating higher stress resistance. In agreement, lipid peroxidation (HNE-His adducts) increased in old age, although protein oxidation (carbonyl groups) showed no increase. In conclusion, features of wasting WAT were similar in the four depots, including decreased adipocyte sizes and alterations in protein expression profiles that indicated decreased insulin sensitivity and increased lipid peroxidation.
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Affiliation(s)
- Lucila Sackmann-Sala
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- Molecular and Cellular Biology Program, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Darlene E. Berryman
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- Molecular and Cellular Biology Program, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- School of Applied Health Sciences and Wellness, College of Health Sciences and Professions, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Ellen R. Lubbers
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Clare B. Vesel
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Katie M. Troike
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Edward O. List
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Rachel D. Munn
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
| | - Yuji Ikeno
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245 USA
| | - John J. Kopchick
- Edison Biotechnology Institute, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- Molecular and Cellular Biology Program, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
- Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, 1 Water Tower Dr., The Ridges, Athens, OH 45701 USA
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