Gene-experience interaction alters the cholinergic septohippocampal pathway of mice

Spatial learning requires the septohippocampal pathway. The interaction of learning experience with gene products to modulate the function of a pathway may underlie use-dependent plasticity. The regulated release of nerve growth factor (NGF) from hippocampal cultures and hippocampus, as well as its actions on cholinergic septal neurons, suggest it as a candidate protein to interact with a learning experience. A method was used to evaluate NGF gene-experience interaction on the septohippocampal neural circuitry in mice. The method permits brain region-specific expression of a new gene by using a two-component approach: a virus vector directing expression of cre recombinase; and transgenic mice carrying genomic recombination substrates rendered transcriptionally inactive by a “floxed” stop cassette. Cre recombinase vector delivery into transgenic mouse hippocampus resulted in recombination in 30% of infected cells and the expression of a new gene in those cells. To examine the interaction of the NGF gene and experience, adult mice carrying a NGF transgene with a floxed stop cassette (NGFXAT) received a cre recombinase vector to produce localized unilateral hippocampal NGF gene expression, so-called “activated” mice. Activated and control nonactivated NGFXAT mice were subjected to different experiences: repeated spatial learning, repeated rote performance, or standard vivarium housing. Latency, the time to complete the learning task, declined in the repeated spatial learning groups. The measurement of interaction between NGF gene expression and experience on the septohippocampal circuitry was assessed by counting retrogradely labeled basal forebrain cholinergic neurons projecting to the hippocampal site of NGF gene activation. Comparison of all NGF activated groups revealed a graded effect of experience on the septohippocampal pathway, with the largest change occurring in activated mice provided with repeated learning experience. These data demonstrate that plasticity of the adult spatial learning circuitry can be robustly modulated by experience-dependent interactions with a specific hippocampal gene product.

Conceptualizing The Miscarriage Experience Through The Lens Of Ghosts In The Nursery

The purpose of this doctoral paper was to use the “Ghosts in the Nursery” theory (Fraiberg, Adelson, & Shapiro, 1975) as a framework for understanding clinicians’ perceptions of women’s experience of miscarriage. Specific attention was paid to the experience of becoming pregnant with a subsequent child. Professionals who work in the field of infant mental health were asked to explore the theory’s utility in conceptualizing the experience of becoming pregnant after a miscarriage. Results indicated that the perceptions of women’s experiences of miscarriage and subsequent pregnancy are congruent with previous research findings. Further elaboration and information are provided to illustrate the experience of having a child and being a parent after experiencing a loss, and to explore the idea of understanding miscarriage as a “ghost”. This study applies a new perspective to the theory of “Ghosts in the Nursery” (Fraiberg et al., 1975) to children born after a loss.

Essays in dynamic optimal taxation: working experience, unemployment scarring and poverty

This thesis investigates the design of optimal tax systems in dynamic environments. The first essay characterizes the optimal tax system where wages depend on stochastic shocks and work experience. In addition to redistributive and efficiency motives, the taxation of inexperienced workers depends on a second-best requirement that encourages work experience, a social insurance motive and incentive effects. Calibrations using U.S. data yield higher expected optimal marginal income tax rates for experienced workers for most of the inexperienced workers. They confirm that the average marginal income tax rate increases (decreases) with age when shocks and work experience are substitutes (complements). Finally, more variability in experienced workers' earnings prospects leads to increasing tax rates since income taxation acts as a social insurance mechanism. In the second essay, the properties of an optimal tax system are investigated in a dynamic private information economy where labor market frictions create unemployment that destroys workers' human capital. A two-skill type model is considered where wages and employment are endogenous. I find that the optimal tax system distorts the first-period wages of all workers below their efficient levels which leads to more employment. The standard no-distortion-at-the-top result no longer holds due to the combination of private information and the destruction of human capital. I show this result analytically under the Maximin social welfare function and confirm it numerically for a general social welfare function. I also investigate the use of a training program and job creation subsidies. The final essay analyzes the optimal linear tax system when there is a population of individuals whose perceptions of savings are linked to their disposable income and their family background through family cultural transmission. Aside from the standard equity/efficiency trade-off, taxes account for the endogeneity of perceptions through two channels. First, taxing labor decreases income, which decreases the perception of savings through time. Second, taxation on savings corrects for the misperceptions of workers and thus savings and labor decisions. Numerical simulations confirm that behavioral issues push labor income taxes upward to finance saving subsidies. Government transfers to individuals are also decreased to finance those same subsidies.

AID assistance to local government : experience and issues /

"PN-AAL-026"--Cover.

AID's experience with contraceptive social marketing : a synthesis of project findings /

"PN-AAL-073"--Cover.

The effect of truck size and weight on accident experience and traffic operations. Volume 1: executive summary. Final report.

Federal Highway Administration, Washington, D.C.

The effect of truck size and weight on accident experience and traffic operations. Volume II: traffic operations. Final report.

Federal Highway Administration, Washington, D.C.

The effect of truck size and weight on accident experience and traffic operations. Volume III: accident experience of large trucks. Final report.

Federal Highway Administration, Washington D.C.

Pedestrian safety programs - a review of the literature and operational experience. Final report.

Federal Highway Administration, Office of Research, Washington, D.C.

Floating breakwater field experience, West Coast /

Mode of access: Internet.

Basic education in manpower programs : the R & D experience : [report] /

Includes bibliographical references.

The Bellevue experience : a case study.

Mode of access: Internet.

What can state and regional health planners learn from the Canadian experience in regulating hospital services /

"HRP-0901082."