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Title:Development of the adolescent prefrontal cortex and basolateral amygdala and the effects of puberty and alcohol exposure
Author(s):Koss, Wendy
Director of Research:Juraska, Janice M.
Doctoral Committee Chair(s):Juraska, Janice M.
Doctoral Committee Member(s):Gulley, Joshua M.; Galvez, Roberto; Raetzman, Lori T.
Department / Program:Psychology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Prefrontal Cortex
Basolateral Amygdala
Dendritic Spines
Abstract:Human structural magnetic resonance imaging (MRI) studies indicate that some neural regions such as the prefrontal cortex (PFC) and the amygdala continue to develop throughout adolescence into early adulthood. These studies have specifically shown that the volume of the PFC increases until puberty and then decreases until early adulthood. By contrast, the amygdala has been shown to increase in volume through the adolescent period. Using the rat as a model of these changes, our laboratory has previously found that both of these structures show a decreasein the number of neuronsbetween postnatal day (P) 35 and P90, the equivalent adolescent period in the rat(Markham et al, 2007; Rubinow and Juraska, 2009). The studies described here were designed to further elucidate neuroanatomical changes in the brain during the adolescent period as well as investigate how intrinsic and extrinsic factors may disrupt this development. In chapter 2, adolescents and adults were compared in a behavioral task dependent on the medial prefrontal cortex (mPFC). Adolescents were able to perform the task. On certain delays (15s and 30s), however, they were consistently worse than adults indicating that behavior that depends on the mPFC is not yet at adult levels. To identify further neuroanatomical changes in the mPFC and the basolateral amygdala (BLA),dendritic arborizationsand dendritic spines were analyzed in chapter 3. These studies indicated a growth of dendrites and dendritic spines between P20 and P35 (prepuberty) in both sexes as well as both structures. After P35, the dendrites of the mPFC were shown to prune predominately in females, whereas in the BLA,dendrites slightly increased in length but significantly increased in the number of branches in both sexes.During this period of neuroanatomical change,adolescent rats were exposed to alcohol in a binge-like manner and then sacrificed in adulthood to quantify the number of neurons and glia. Results reported in chapter 4 revealed no significant differences in the total number of neurons in the mPFC. However there was a significant decrease in glia that occurred in the male mPFC. No differences were found in any measure in the BLA. In chapter 5, pubertal hormones were removed by ovariectomizing or castrating animals prior to puberty. Results showed that removal of the testes caused no effects in males but there were changes in the number of neurons and glia in females. It was found that females without ovaries during puberty had more neurons and a greater number of glia, thus eliminating sex differences. Taken together these experimentsreveal further neuroanatomical changes in the mPFC and the BLA. Furthermore they highlight how pubertal hormones are involved in the adolescent development of the mPFC and the cellular effects of alcohol use within the adolescent period.
Issue Date:2013-08-22
Rights Information:Copyright 2013 Wendy Koss
Date Available in IDEALS:2013-08-22
Date Deposited:2013-08

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