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    The Development of a Match to Sample Memory Task and Test of Impulsivity to Investigate Rat Models of Schizophrenia
    (2007) Pammer, Dave; Mauch, Tiffany; Day, Arden; KIipec, W. D.
    Animal models of schizophrenia have been developed using chronic exposure to the dissociative anesthetics phencycladine (PCP) and ketamine to induce psychosis in rats. Preliminary research in our laboratory has shown marginal effects of low doses of PCP on the rat P300 event related potential (ERP) similar to those found in human male schizophrenics. As part of a broader program of research investigating the P300 ERP in a rat model of schizophrenia, we have been developing a battery of behavioral paradigms to test for memory deficits and impulsiveness that can be used to differentiate schizophrenic-like behavior from normal behavior in rats. The present research is directed toward developing a Y-maze match to sample (MTS) and a two lever MTS paradigm to screen for memory deficits. In these tests the rat receives a water reinforcer only if it chooses to run to the alley that was lighted or press the lever that was lighted during the sample phase. Memory is tested by inserting a delay interval during which the light cue disappears and the response is prevented. We are also developing a test of impulsivity in which the rat must inhibit a nose poke response until the third brief presentation of a light to obtain a water reinforcer. Early nose pokes result in a time out. Olin Hall construction delayed the initiation of this experiment. Accordingly preliminary results will be presented.
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    Neuropil Distribution In The Anterior Cingulate And Primary Visual Cortex Of Cetartiodactyla, Primates, and Afrotheria
    (2014-04-17) Nguyen, Amy; Patzke, Nina; Bitterman, Kathleen; Manger, Paul; Spocter, Mohammad
    Previous studies of the cerebral cortex have utilized the neuropil space as a proxy for connectivity, highlighting structural differences between cortical areas. The following study aims to investigate the distribution of neuropil space across 18 mammalian orders in two cortical areas, sampled from the frontal and occipital lobes. Results indicate a significant difference in neuropil space between cortical areas and species. The anterior cingulate cortex maintained a higher neuropil fraction than the primary visual cortex among all species studied.
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    Pulse-Shape Effects On The Autler-Townes Doublet In Strong-Field Ionization Of Atomic Hydrogen
    (2014-04-17) Emmons, John; Buczek, Sean
    A characteristic feature in strong-field multi-photon ionization processes is the so-called Autler-Townes Doublet [1] that occurs due to the transient splitting of atomic energy levels in the electric field of the laser pulse. Preliminary studies [2] revealed that the shape of this doublet structure can be strongly dependent on the details of the pulse structure. This dependence is not only surprising, but may also be a limiting factor on the ability of calibrating absolute laser intensities [3]. [1] S. H. Autler and C. H. Townes, Phys. Rev. 100 (1955) 703. [2] A. N. Grum-Grzhimailo, M. N. Khaerdinov, and K. Bartschat, Phys. Rev. A 88 (2013) 055401. [3] M. G. Pullen et al., Phys. Rev. A 87 (2013) 053411
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    Parallelizable Algorithms For Describing The Effects Of Strong Time-Dependent Electromagnetic Fields On The Hydrogen Atom
    (2014-04-17) Emmons, John; Howes, Austin; Kramer, Alex; Guan, Xiaoxu
    We are testing a variety of methods to numerically treat the ionization of atomic hydrogen by a strong lase r pulse. Besides providing high accuracy, the algorithms should be parallelizable in order to handle the sometimes long propagation times needed to solve the time-dependent Schrödinger equation for this fundamental strong-field problem. We report progress on developing a computer code that will make such calculations possible on massively parallel supercomputer platforms.
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    Estimation Of The Social Discount Rate For Non-Marginal Environmental Damages
    (2014-04-11) Parrish, Conor
    When estimating the costs and benefits of programs to address long-term environmental challenges like climate change, the choice of discount rate often drives the results. The Pure Rate of Time Preference (PTP) used in major analyses have ranged from 0.1% (Stern) to 3% (Nordhaus) or higher. In many studies, high values of PTP are supported by revealed preference information based on marginal changes. However, many of the expected effects of climate change are likely to be non-marginal, including extinction, loss of entire habitat types, and inundation of small nations. We report on efforts to measure PTP for non-marginal changes by asking individuals to choose between protecting all of a particular type of habitat for a fixed number of years, versus a fraction of the habitat indefinitely. Presenting individuals with this trade-off provides a way to assess preferences that is easy for the participant to understand, potentially realistic, and not subject to many of the confounding factors that plague current techniques.