Publications by authors named "Marissa Penrose"

Background: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique that uses magnetic pulses over the cranium to induce electrical currents in underlying cortical tissue. Although rTMS has shown clinical utility for a number of neurological conditions, we have only limited understanding of how rTMS influences cellular function and cell-cell interactions.

Objective: In this study, we sought to investigate whether repeated magnetic stimulation (rMS) can influence astrocyte biology in vitro.

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Repetitive transcranial magnetic stimulation (rTMS), a non-invasive form of brain stimulation, has shown experimental and clinical efficacy in a range of neuromodulatory models, even when delivered at low intensity (i.e. subthreshold for action potential generation).

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Peripheral nerve (PN) grafts can be used to bridge tissue defects in the CNS. Using a PN-to-optic nerve (ON) graft model, we combined gene therapy with pharmacotherapy to promote the long-distance regeneration of injured adult retinal ganglion cells (RGCs). Autologous sciatic nerve was sutured onto the transected ON and the distal end immediately inserted into contralateral superior colliculus (SC).

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Purpose: In adult rats, intravitreal injections of the Rho-GTPase inhibitor C3 transferase (BA-210), or a cocktail of recombinant ciliary neurotrophic factor (CNTF) and a cyclic AMP analogue (CPTcAMP), increase retinal ganglion cell (RGC) survival and axonal regeneration. Here we examined whether these treatments also affect the dendritic architecture of regrowing RGCs.

Methods: In Fischer F344 rats, one optic nerve was cut and an autologous peripheral nerve graft was sutured onto it.

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The conditional expression of alternative phenotypes underlies the production of almost all life history decisions and many dichotomous traits, including male alternative reproductive morphs and behavioral tactics. Changes in tactic fitness should lead to evolutionary shifts in developmental switch points that underlie tactic expression. We used experimental evolution to directly test this hypothesis by rearing ten generations of the male-dimorphic mite Rhizoglyphus echinopus in either simple or three-dimensionally complex habitats that differed in their effects on morph fitness.

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The mutation-selection-balance model predicts most additive genetic variation to arise from numerous mildly deleterious mutations of small effect. Correspondingly, "good genes" models of sexual selection and recent models for the evolution of sex are built on the assumption that mutational loads and breeding values for fitness-related traits are correlated. In support of this concept, inbreeding depression was negatively genetically correlated with breeding values for traits under natural and sexual selection in the weevil Callosobruchus maculatus.

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