A comprehensive understanding of how image processing occurs in the primary visual cortex (V1) requires learning what aspects of neuronal responses are driven by strong feed-forward input from the lateral geniculate nucleus (LGN), and what aspects arise due to the densely recurrent network operating within the cortex itself. From an...
The nervous system develops through the highly regulated process of proliferation and differentiation of neural stem cells. Two major regulatory pathways that maintain neural stem cells in a proliferative state or promote their differentiation are the Notch and BMP signaling pathways, respectively. In this dissertation, we demonstrate that HeyL, a...
Development of the central nervous system requires the coordinated interplay of intrinsic and extrinsic factors. I examined the actions of an extrinsic factor, TWEAK, and an intrinsic factor, Iroquois1 (Irx1) on neural progenitor cell behavior. Embryonic day 12 (E12) and post-natal day 1 (PN1) neural progenitor cells both express Fn14,...
Gonadotropin releasing hormone (GnRH) neurons comprise the final pathway through which the central nervous system exerts its control over the hypothalamic-pituitary-gonadal (HPG) axis. GnRH is released in a pulsatile manner, and conveyed to the anterior pituitary gland to stimulate synthesis and secretion of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating...
Primary progressive aphasia (PPA) is a debilitating neurodegenerative syndrome that principally impairs the cognitive domain of language. Patients demonstrate deficits in a variety of language faculties including object naming (anomia), word finding, single word and sentence reading, speech comprehension, repetition, syntactic processing, and paraphasia. PPA has been associated with selective...
Alzheimer's disease (AD) is a progressive amnestic dementia typified by the pathological self-association of the microtubule-associated tau protein into neurofibrillary tangles (NFTs). Important to NFT formation are numerous modifications of tau, including phosphorylation, truncation, and conformational changes. In addition, AD-associated inflammation promotes the formation of peroxynitrite (ONOO-), a potent nitrating...
A comprehensive understanding of human memory requires both cognitive and neural descriptions of memory processes along with a conception of how memory processing drives behavioral responses and subjective experiences. Noninvasive neuroimaging techniques have greatly extended our understanding of the functional characteristics of human memory, and how neural events give rise...
Primary Progressive Aphasia (PPA) is an aphasic dementia syndrome caused by neurodegenerative disease in which linguistic abilities are selectively disrupted in the relative absence of other cognitive deficits in early stages. The studies presented in this thesis were designed to examine the integrity of word and object processing by contrasting...
Information processing in the striatum is crucial for voluntary movement control and associative learning and in the normal condition is subject to balanced dopaminergic and cholinergic modulation. However, in Parkinson's disease (PD) striatal dopamine (DA) level falls because of degeneration of DA neurons in the substantia nigra pars compacta and...
The goal of this dissertation was to examine the influence of motivational incentives on visual spatial attention in patients with probable Alzheimer's Disease (PRAD), patients with mild cognitive impairment (MCI) and healthy age-matched control subjects (EC). Specifically, I compared the ability of monetary incentives to influence behavioral and neural performance...