Dentate gyrus-selective colchicine lesion and performance in temporal and spatial tasks

Costa, Valéria Catelli Infantozzi; Bueno, José Lino Oliveira; Xavier, Gilberto Fernando

doi:10.1016/j.bbr.2004.12.011

Cited by 30 publications

(42 citation statements)

References 71 publications

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“…The most prominent neuroanatomical target of these studies had been the limbic system, which is also implicated in interval timing [26][27][28][29][30][31][32][33][34][35]. For instance, hippocampus [27][28][29]33,35] and amygdala [33] lesions have been shown to result in clear impairments of DRL performance in the form of increased responses per reinforcer. Unfortunately, many of these reports did not present the complete response curves, which does not enable the characterization of observed deficiencies differentially as being due to an increase in frequency of non-timed responses (exponential portion of our mixture model) or due to a leftward shift of the timed response curve (inverse-Gaussian portion of our mixture model) or both.…”

Section: Discussionmentioning

confidence: 99%

Time-based reward maximization

Çavdaroğlu

Zeki

Balcı

2014

Phil. Trans. R. Soc. B

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Humans and animals time intervals from seconds to minutes with high accuracy but limited precision. Consequently, time-based decisions are inevitably subjected to our endogenous timing uncertainty, and thus require temporal risk assessment. In this study, we tested temporal risk assessment ability of humans when participants had to withhold each subsequent response for a minimum duration to earn reward and each response reset the trial time. Premature responses were not penalized in Experiment 1 but were penalized in Experiment 2. Participants tried to maximize reward within a fixed session time (over eight sessions) by pressing a key. No instructions were provided regarding the task rules/parameters. We evaluated empirical performance within the framework of optimality that was based on the level of endogenous timing uncertainty and the payoff structure. Participants nearly tracked the optimal target inter-response times (IRTs) that changed as a function of the level of timing uncertainty and maximized the reward rate in both experiments. Acquisition of optimal target IRT was rapid and abrupt without any further improvement or worsening. These results constitute an example of optimal temporal risk assessment performance in a task that required finding the optimal trade-off between the ‘speed’ (timing) and ‘accuracy’ (reward probability) of timed responses for reward maximization.

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Section: Discussionmentioning

confidence: 99%

Time-based reward maximization

Çavdaroğlu

Zeki

Balcı

2014

Phil. Trans. R. Soc. B

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“…The ability to learn and retain the MWT depends on an intact dentate gyrus [6,31,33]. Within the dentate gyrus, more DCX expressing neurons were observed in rats that received spatial navigation training 30 days prior to the day they were sacrificed than in swim controls or home cage controls.…”

Section: Discussionmentioning

confidence: 99%

Persistent increases in the pool of doublecortin-expressing neurons in the hippocampus following spatial navigation training

Keith

Priester

Ferguson

et al. 2008

Behavioural Brain Research

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In addition to its role in neuronal migration during embryonic development, doublecortin (DCX) plays a role in hippocampal neurogenesis across the lifespan. Hippocampal neurons exhibit a high degree of synaptic plasticity while they are in the DCX phase. While previous studies have reported that behavioral training on hippocampus-dependent tasks can enhance neuron survival, little was known about the stage of development of those neurons and, particularly, whether a large pool of the surviving new neurons remains in the DCX phase for a prolonged period after training. Here we report that spatial navigation training increases the pool of neurons that are in the DCX phase four weeks after training ended. Thus, the stock of DCX-expressing neurons in the hippocampus is affected by whether a hippocampus-dependent task has been encountered during the preceding few weeks.

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“…Os índices de eficiência (porcentagem de acertos na tarefa) foram maiores quando os sujeitos eram alimentados antes de cada sessão de DRL-20 s (Costa, Bueno, & Xavier, 2005) do que quando os animais, submetidos à mesma tarefa, não receberam alimentação suplementar (Bueno, Costa, Xavier, & Dima, 2006). Costa et al (2005) mantinham ratos em regime de privação de 80% do peso ad lib e 20 minutos antes de cada sessão de DRL-20 s, os animais recebiam quatro gramas de comida como suplemento.…”

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“…Costa et al (2005) mantinham ratos em regime de privação de 80% do peso ad lib e 20 minutos antes de cada sessão de DRL-20 s, os animais recebiam quatro gramas de comida como suplemento. Tais animais, após aquisição da tarefa, apresentaram um desempenho de aproximadamente 85% de eficiência.…”

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“…Exemplos desse caso são estudos em esquemas de DRL que utilizam 98% do peso ad lib (Costa, 2003); 85% do peso ad lib (Acsadi, Buzsaki, Keszthelyi, Kiralyfalvi, & Gage, 1986;Fletcher, 1995;Jarrard & Becker, 1977;Johnson, Olton, Gage, & Jenko, 1977;Kirk, Berntson, & Hothersall, 1982;Pellegrino & Clapp, 1971;Schmaltz, Wolf, & Trejo, 1973) ou ainda, 75% do peso ad lib (Skuban & Richardson, 1975). Existem também variações dos regimes acima mencionados, como por exemplo, 80% do peso ad lib mais 4 gramas de comida 20 minutos antes da tarefa (Costa et al, 2005) ou 85% do peso ad lib, acrescentando-se 1% do peso ad lib por semana (Bannerman et al, 1999).…”

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Desempenho de ratos em um esquema de DRL sob diferentes níveis de privação alimentar

Bueno¹,

Lopes-Aguiar²,

Costa³

2009

Psicol. Reflex. Crit.

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ResumoO esquema de reforçamento diferencial de baixas taxas (DRL) é amplamente utilizado em estudos de comportamentos relacionados à discriminação temporal. Porém, não está claro quais são os efeitos de diferentes níveis de privação em esquemas temporais, especialmente em DRL. O presente estudo testou a hipótese de que privações mais severas prejudicariam o desempenho de sujeitos sob controle do DRL, comparado com os submetidos a privações mais brandas. Três grupos de ratos submetidos inicialmente a três diferentes níveis de privação alimentar (80, 90 e 100% do peso ad lib) foram treinados em DRL-20 s. Após o treino, realizou-se uma manipulação intra-grupos em duas condições sucessivas de teste: o grupo de privação 80% passou para 100% e o de 100% passou para 80%; o grupo 90% permaneceu nessa condição ao longo de todo o experimento como grupo-controle. Os animais apresentaram um pior desempenho na tarefa quando a transição da privação foi de 100% para 80% do peso ad lib e uma melhora de desempenho quando a transição foi de 80% para 100% ad lib. Não houve alteração de desempenho quando a transição foi de 90% para 100% ou para 80% ad lib. Os resultados indicam que o desempenho de ratos em uma tarefa de DRL é influenciado não só pelo estado gerado por um nível de privação alimentar específico, mas também por experiências de estados fisiológicos e cognitivos adquiridos em situações anteriores. Palavras-chave: Ratos; DRL; privação alimentar; intervalo entre respostas. AbstractThe scheme of differential reinforcement of low response rates (DRL) is largely employed in behavioral studies of temporal discrimination. However, it is not clear what the behavioral effects of different deprivation levels on the behavior under the control of temporal schemes of reinforcement are, especially the DRL. The present study tested the hypothesis that more severe deprivation disrupts the subjects' performance under DRL control, compared to that of subjects exposed lower levels of deprivation. Three groups of rats initially submitted to three different food deprivation levels (80, 90 and 100% ad lib) were trained under a DRL-20 s scheme. After the training, deprivation was manipulated intra-group, in two consecutive testing conditions: the deprivation of the 80% group was changed to 100% ad lib and deprivation of the 100% group was changed to 80% ad lib; the 90% deprived group was kept under this level of deprivation across all experimental sessions as a controlgroup. The animals showed a worse performance in the DRL task when the deprivation transition went from 100% to 80% ad lib and a better performance when the transition was from 80% to 100% ad lib. There were no systematic changes in performance under the transitions from 90% to 100% or from 90% to 80% ad lib. The results indicate that the rats performance in a DRL is affected not only by the state generated by a specific level of food deprivation, but also by physiological and cognitive states acquired in preceding situations.

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Dentate gyrus-selective colchicine lesion and performance in temporal and spatial tasks

Cited by 30 publications

References 71 publications

Time-based reward maximization

Time-based reward maximization

Persistent increases in the pool of doublecortin-expressing neurons in the hippocampus following spatial navigation training

Desempenho de ratos em um esquema de DRL sob diferentes níveis de privação alimentar

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