The effect of orbital prefrontal cortex lesions on performance on a progressive ratio schedule: implications for models of inter-temporal choice

Kheramin, S.; Body, S.; Miranda, Florencio; Bradshaw, C. M.; Szabadi, E.; Deakin, Bill; Anderson, Ian M.

doi:10.1016/j.bbr.2004.05.017

Cited by 68 publications

(78 citation statements)

References 43 publications

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“…This relative increase in perseverative responding is consistent with outcomes stemming from damage to the cerebral cortex, the region most heavily targeted by gestational MeHg exposure (Barone et al, 1998;Berlin et al, 1975;Burbacher et al, 1990;O'Kusky, 1983;Rice, 1983). Lesions within the cortex lead to increases in perseveration on discrimination reversal procedures (Chudasama and Robbins, 2003;Ridley et al, 1993), and they also increase responding on large ratio reinforcement schedules (Kheramin et al, 2005), consistent with MeHg effects reported in Paletz et al, 2006(see Newland et al, 2006a. Cortical regions also appear to mediate behavioral choice (Schultz et al, 2000;Tremblay and Schultz, 1999) in situations like the SDR (and VDR) and concurrent schedules.…”

Section: Mehg and Behavioral Transitionssupporting

confidence: 63%

Spatial and visual discrimination reversals in adult and geriatric rats exposed during gestation to methylmercury and n−3 polyunsaturated fatty acids

et al. 2007

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Fish contain essential long chain polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA), an omega-3 (or n-3) PUFA, but are also the main source of exposure to methylmercury (MeHg), a potent developmental neurotoxicant. Since n-3 PUFAs support neural development and function, benefits deriving from a diet rich in n-3s have been hypothesized to protect against deleterious effects of gestational MeHg exposure. To determine whether protection occurs at the behavioral level, female Long-Evans rats were exposed, in utero, to 0, 0.5, or 5 ppm of Hg as MeHg via drinking water, approximating exposures of 0, 40, and 400 μg Hg/kg/day and producing 0, 0.29, and 5.50 ppm of total Hg in the brains of siblings at birth. They also received pre-and postnatal exposure to one of two diets, both based on the AIN-93 semipurified formulation. A "fish-oil" diet was high in, and a "coconut-oil" diet was devoid of, DHA. Diets were approximately equal in α-linolenic acid and n-6 PUFAs. As adults, the rats were first assessed with a spatial discrimination reversal (SDR) procedure and later with a visual (nonspatial) discrimination reversal (VDR) procedure. MeHg increased the number of errors to criterion for both SDR and VDR during the first reversal, but effects were smaller or nonexistent on the original discrimination and on later reversals. No such MeHg-related deficits were seen when the rats were retested on SDR after two years of age. These results are consistent with previous reports and hypotheses that gestational MeHg exposure produces perseverative responding. No interactions between Diet and MeHg were found, suggesting that n-3 PUFAs do not guard against these behavioral effects. Brain Hg concentrations did not differ between the diets, either. In geriatric rats, failures to respond were less common and response latencies were shorter for rats fed the fish oil diet, suggesting that exposure to a diet rich in n-3s may lessen the impact of age-related declines in response initiation.

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Section: Mehg and Behavioral Transitionssupporting

confidence: 63%

Spatial and visual discrimination reversals in adult and geriatric rats exposed during gestation to methylmercury and n−3 polyunsaturated fatty acids

et al. 2007

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“…Studies in animal models also suggest an importance of gonadal steroid stimulation for prefrontal cortical function in males. For example, gonadectomy in adult male rats has been shown to significantly impair performance in maze and operant tests of spatial (Daniel et al, 2003;Kritzer et al, 2007;Kritzer et al, 2001) and non-spatial (Ceccarelli et al, 2001) working memory and behavioral flexibility (Kritzer et al, 2007), which are processes that are dependent on the medial prefrontal cortices (Dias and Aggleton, 2000;Kesner et al, 1996;Lacroix et al, 2002;Schwabe et al, 2004;Taylor et al, 2003), as well as performance on a progressive reward ratio task (Kritzer et al, 2007) which is sensitive to lesions of the orbital prefrontal cortices (Kheramin et al, 2005). In this study, analyses of hormone sensitivity were extended to a task sensitive in part to lesions of the perirhinal prefrontal cortices, a spontaneous novel object recognition (NOR) task, to test the hypothesis that functions mediated by this third major division of the prefrontal cortex may also be sensitive to long-term gonadectomy and hormone replacement in adult male subjects.…”

Section: Introductionmentioning

confidence: 99%

Effects of gonadectomy and hormone replacement on a spontaneous novel object recognition task in adult male rats

Aubele

Kaufman²,

Montalmant

et al. 2008

Hormones and Behavior

105

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Recent studies in adult male rats have shown that gonadal hormones influence performance on certain working memory and other types of cognitive tasks that are sensitive to lesions of the medial and/or orbital prefrontal cortices. This study asked whether gonadal hormone modulation of prefrontal cortical function in males also extends to the perirhinal division of the rat prefrontal cortex. Specifically, sham-operated control, gonadectomized, and gonadectomized rats supplemented with testosterone propionate or estradiol were tested on a spontaneous novel object recognition task, a paradigm where performance has been shown to be impaired by perirhinal cortical lesions. Using analyses of variance, regression analyses and post-hoc testing to evaluate group differences, it was found that during both the sample and test trials of the task all four groups spent similar absolute and proportional amounts of time ambulating, rearing, stationary, and exploring the two objects present. All groups also explored each of the two identical objects present during sample trials equally. However, during the test trials, only the control and gonadectomized rats given testosterone showed the expected increase in exploration of the novel objects presented, whereas the gonadectomized and gonadectomized, estradiol-supplemental groups continued to explore the novel and familiar objects equally. That regression analyses also identified significant correlations between low bulbospongiosus muscle weight and impaired novel vs. familiar object discrimination further indicates that gonadectomy in adult male rats adversely affects spontaneous novel object recognition in an androgen-sensitive, estrogen-insensitive manner.

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“…Mathematical principles of reinforcement (MPR; Killeen, 1994;Killeen & Sitomer, 2003) characterizes response rates on various schedules of reinforcement as a function of three parameters: memory decay rate (λ), motivation (a), and motor ability (δ). MPR has been applied previously in behavioral neuroscience research, to analyze the effects of brain lesions or drugs (Kheramin, Body, Herrera, Bradshaw, Szabadi, Deakin, & Anderson, 2005;Reilly, 2003). At the conclusion of this phase, the influence of chronic stress on spatial memory was assessed using a hippocampaldependent, spatial recognition Y maze.…”

mentioning

confidence: 99%

Chronic stress impairs spatial memory and motivation for reward without disrupting motor ability and motivation to explore.

Kleen

Sitomer

Killeen

et al. 2006

Behavioral Neuroscience

150

112

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This study uses an operant, behavioral model to assess the daily changes in the decay rate of shortterm memory, motivation, and motor ability in rats exposed to chronic restraint. Restraint decreased reward-related motivation by 50% without altering memory decay rate or motor ability. Moreover, chronic restraint impaired hippocampal-dependent spatial memory on the Y maze (4-hr delay) and produced CA3 dendritic retraction without altering hippocampal-independent maze navigation (1-min delay) or locomotion. Thus, mechanisms underlying motivation for food reward differ from those underlying Y maze exploration, and neurobiological substrates of spatial memory, such as the hippocampus, differ from those that underlie short-term memory. Chronic restraint produces functional, neuromorphological, and physiological alterations that parallel symptoms of depression in humans.

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The effect of orbital prefrontal cortex lesions on performance on a progressive ratio schedule: implications for models of inter-temporal choice

Cited by 68 publications

References 43 publications

Spatial and visual discrimination reversals in adult and geriatric rats exposed during gestation to methylmercury and n−3 polyunsaturated fatty acids

Spatial and visual discrimination reversals in adult and geriatric rats exposed during gestation to methylmercury and n−3 polyunsaturated fatty acids

Effects of gonadectomy and hormone replacement on a spontaneous novel object recognition task in adult male rats

Chronic stress impairs spatial memory and motivation for reward without disrupting motor ability and motivation to explore.

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