Developmental Neuroscience Commons^™

Behavioral And Neural Mechanisms Of Impulsive Choice, Jesse Mcclure

Doctoral Dissertations

Impulsive choice is defined as the preference for a small immediate reward over a larger delayed reward. Individual variablity in impulsive choice correlates with many socially relevant behaviors. Although forms of impulsive choice have been studied in both behavioral ecology and psychology, the exchange of knowledge between these fields is just beginning. Drawing from both of these fields will improve our research methods allowing for a more detailed understanding of this complex behavior. Existing tasks to measure impulsive choice conflate the delay and quantity of the reward. To address this, I have drawn from foraging research to establish a method …

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang

Victor R. Ambros

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …

Efficient In Vitro Development Of Photoreceptors From Human Pluripotent Stem Cells, Joseph C. Reynolds

Dissertations, Masters Theses, Capstones, and Culminating Projects

Degeneration of the rod and cone photoreceptors in the human retina is among the most common causes of blindness. Replacing these damaged photoreceptors may help to restore vision. Repairing the damaged retina relies on the insertion of new, healthy cells. Embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are two possible sources of photoreceptors to restore vision. Previous data shows that human ES cells and iPS cells can be differentiated into photoreceptors and transplanted into the eye to restore some vision. However, this process is inefficient, and costly. Here, we show a new method for inducing photoreceptor production …

Role Of Sox11 During Vertebrate Ocular Morphogenesis And Retinal Neurogenesis, Lakshmi Shashidharan Pillai

Theses and Dissertations--Biology

Microphthalmia, anophthalmia, and coloboma (MAC) are distinct abnormalities demonstrating a continuum of developmental eye defects that contribute to 15-20% of blindness and severe vision deficiencies in children worldwide. The genetic etiology of MAC is large, complex and encompasses the whole developmental biology of the eye. Understanding how the eye develops will aid in identifying genes and developmental pathways involved in MAC. Although investigation of the genetic architecture of congenital anomalies is growing exponentially, much work remains to be accomplished to understand the complex, genetically heterogeneous congenital anomalies, which significantly impact childhood vision.

With an interest in elucidating the mechanisms that …

Dual Functions For Insulinoma-Associated 1 In Retinal Development, Marie A. Forbes-Osborne

Theses and Dissertations--Biology

Proper visual system function requires tightly controlled proliferation of a pool of relatively homogeneous retinal progenitor cells, followed by the stepwise specification and differentiation of multiple distinct cell types. These retinal cells, both neuronal and glial, must be generated in the correct numbers, and the correct laminar location to permit the formation of synaptic connections between individual cell types. After synapses are made, constant signaling is required as part of normal retinal function, and to maintain cellular identity and connectivity. These processes rely on both extrinsic and intrinsic signaling, with regulation of gene expression by cascades of transcription factors having …

Pcdh19 Expression In Normal And Regenerating Adult Zebrafish Retinas, Kristin N. Forkapa Ms.

Williams Honors College, Honors Research Projects

My Honors Research Project will test the function of the N-cadherin molecule on the zebrafish optic nerve regeneration. N-cadherin is a member of the cadherin superfamily. Cadherins are cell adhesion molecules important for animal development and maintenance of adult structures. Unlike mammals, fish and amphibians have the ability to regenerate their optic nerve after damages. Molecular mechanisms underlying the optic nerve regeneration are still under intense investigation. Studies in Dr. Liu’s laboratory showed that expression of several cadherins, including N-cadherin, was greatly increased during adult zebrafish optic nerve regeneration, suggesting that cadherins may be involved in the optic nerve regeneration …