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      Prenatal PolyI:C induced schizophrenia-like cognitive inflexibilities in the male, but not female, rat adult offspring

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      Zhang_Ying_MA_thesis_Aug_2011.pdf (922.0Kb)
      Date
      2011-07
      Author
      Zhang, Ying
      Type
      Thesis
      Degree Level
      Masters
      Metadata
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      Abstract
      Executive functions are important cognitive processes critical for survival. Damage to the prefrontal cortex impairs executive functions, such as working memory, decision making and set-shifting. Interestingly, patients diagnosed with different psychiatric disorders are also impaired in executive functions, especially in the set-shift domain, often measured by the Wisconsin Card Sorting Task (WCST). Set-shifting is an essential cognitive process, in that it allows the individual to suppress non-reinforcing strategies and engage in new rewarding strategies. To date, little is known about the etiology of executive dysfunction in psychiatric disorders. However, some epidemiological and serological experiments have shown strong correlations between prenatal infection and the increased risk to develop psychiatric disorders in the adult offspring. One study found that schizophrenic patients pre-exposed to a prenatal infection perseverated more during the WCST, than non-pre-exposed patients. Despite these findings, there are still numerous limitations (e.g., ethical concerns) when conducting these studies. Thus, animal models are important and can further elucidate the etiology of executive dysfunctions in psychiatric disorders. Prenatal infection animal models have consistently shown that inflammation during gestation in rodents induces behavioural, anatomical and cognitive changes in the adult offspring similar to psychiatric patients. However, no studies have investigated the effects of prenatal infection on set-shifting in the adult offspring. Therefore, the present thesis examined whether prenatal treatment with PolyI:C (a viral mimetic) during middle/late gestation of the rat would induce cognitive inflexibilities (i.e., set-shifting and reversal learning in an operant based task analogous to the WCST) in the adult male and female offspring. The results showed PolyI:C male offspring perseverated during the set-shift but had fewer regressive errors during the reversal learning day. PolyI:C treated female offspring were not impaired during any of the test days; however, females were slower to respond to the lever and required more training when compared the male rats. Taken together, these results give support for prenatal infection in inducing cognitive inflexibility, by potentially altering the PFC in the adult offspring. MS-based thesis: Zhang, Y., Cazakoff, B. N., Thai, C. A., & Howland, J. G. (2011). Prenatal exposure to a viral mimetic alters behavioural flexibility in male, but not female, rats. Neuropharmacology, [epub ahead of print]. doi:10.1016/j.neuropharm.2011.02.022
      Degree
      Master of Arts (M.A.)
      Department
      Psychology
      Program
      Psychology
      Supervisor
      Howland, John G.
      Committee
      Bowen, Angela N.; Kalynchuk, Lisa E.; Borowsky, Ron
      Copyright Date
      July 2011
      URI
      http://hdl.handle.net/10388/etd-07142011-120132
      Subject
      prenatal infection
      rat
      schizophrenia
      reversal learning
      set-shifting
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      • Graduate Theses and Dissertations
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