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Activity of brainstem cholinergic neurons during 22 kHz ultrasonic vocalization in rats /

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Show simple item record Iku, Nwamaka. en_US 2009-06-09T18:16:23Z 2009-06-09T18:16:23Z 2007-06-09T18:16:23Z
dc.description.abstract Adult rats emit 22 kHz ultrasonic alann calls in aversive situations. This type of call IS a component of defensive behaviour and it functions predominantly to warn conspecifics about predators. Production of these calls is dependent on the central cholinergic system. The laterodorsal tegmental nucleus (LDT) and pedunculopontine tegmental nucleus (PPT) contain largely cholinergic neurons, which create a continuous column in the brainstem. The LDT projects to structures in the forebrain, and it has been implicated in the initiation of 22 kHz alarm calls. It was hypothesized that release of acetylcholine from the ascending LDT terminals in mesencephalic and diencephalic areas initiates 22 kHz alarm vocalization. Therefore, the tegmental cholinergic neurons should be more active during emission of alarm calls. The aim of this study was to demonstrate increased activity of LDT cholinergic neurons during emission of 22 kHz calls induced by air puff stimuli. Immunohistochemical staining of the enzyme choline acetyltransferase identified cell bodies of cholinergic neurons, and c-Fos immunolabeling identified active cells. Double labeled cells were regarded as active cholinergic cells. There were significantly more (p<O.05) c-Fos labeled cells in the LDT of vocalizing animals than in control (non-vocalizing air puffed and naIve non-airpuffed) animals. Although the numbers were low, there were also significantly more (p<O.05) doublelabeled neurons in the LDT of vocalizing animals than in the non-vocalizing controls. Such a difference between vocalizing and control animals was not found in the neighbouring PPT nucleus. Results suggest that there are cholinergic and non-cholinergic cells, which are selectively active in the LDT during emission of 22 kHz alarm calls. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Brain stem en_US
dc.subject Rats en_US
dc.title Activity of brainstem cholinergic neurons during 22 kHz ultrasonic vocalization in rats / en_US
dc.type Electronic Thesis or Dissertation en_US M.Sc. Biological Sciences en_US Masters en_US
dc.contributor.department Department of Biological Sciences en_US Faculty of Mathematics and Science en_US

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