Browsing by Subject "Rat"

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    Verification of AMPK Knockdown in Sprague Dawley Rats using a Vivo-Morpholino Antisense Oligonucleotide
    (2024-01-09) Hunsader, Peter; Hernandez, Edith; Moore, Maddi; Slosky, Lauren; Spencer, Sade
    Metformin, a drug typically used to treat type II diabetes, can decrease cue-induced cocaine seeking in rats. The proposed mechanism of action for this effect is the activation of adenosine monophosphate-activated protein kinase (AMPK). To confirm this mechanism for the effect of metformin we are validating a technique for knocking down AMPK in the nucleus accumbens core (NAcC) in vivo. This study tests whether microinjections of a vivo-morpholino antisense oligonucleotide (VM-ASO) in the NAcC is an effective method of knocking down AMPK in Sprague Dawley rats. VM-ASO binds target mRNA and prevents translation. This experiment used 8 Sprague Dawley rats (6 male, 2 female). Initially, rats underwent stereotaxic intracranial surgery for the insertion of a cannula into both hemispheres of the NAcC (from bregma: AP +1.5; ML: +/- 1.8; DV: - 5.5mm). Then, 140 pmol of AMPK VM-ASO or scrambled control nucleotide was microinjected in each hemisphere at a rate of 0.2 µl/minute 2mm below the base of the cannula. After a one-minute diffusion period, the microinjectors were removed. This process was repeated for four days. Eight days after the last microinjection, tissue samples were collected and AMPK levels were analyzed via western blot. It was found that microinjections of AMPK VM-ASO did not significantly decrease AMPK levels in the NAcC.
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    Which way do I go? Strategic representations in rat prefrontal cortex on spatial decision tasks
    (2014-10) Powell, Nathaniel
    The role of the Prefrontal Cortex (PFC) in animal behavior is both complex and subtle. This dissertation concerns the role of rat PFC on spatial decision- making tasks, particularly how it represents strategies or rules necessary to solve these tasks. First I review the current state of knowledge about the role of the rat PFC in regard to behavior and decision-making (Chapter 1). Then I describe the spatial decision-making tasks and electrophysiological recording techniques I used to explore the role of PFC in rats (Chapter 2). Using one of these tasks, I found overlapping populations of PFC neurons that simultaneously encoded mul- tiple relevant task parameters, including some cases in which mulitple parameters were encoded by single neurons (Chapter 3). I also describe the spatial firing properties of PFC neurons on these tasks and conclude that although these cells do not seem to directly represent space per se, there are important differences in both single-cell and population representations that corresponded to the ani- mal's location on spatial tasks (Chapter 4). Finally, using a population decoding approach that takes advantage of the spatially coded information in the cells, I identify transitions between different strategic representations in the PFC of an- imals performing these tasks. In general the transition between states occurred after animals received information that caused them to change their strategy but before the actual change in their behavior. Additionally, these transitions cannot be accounted for solely on the basis of changes to either sensory information or mo- tor output, which proves that these transitions between strategic representational states are cognitive processes (Chapter 5).