Neuroscience and Neurobiology Commons^™

Synaptic Architecture Of The Acoustic Startle Response Pathway, Mahabba Smoka

Electronic Thesis and Dissertation Repository

The acoustic startle response (ASR) is mediated by a simple pathway which includes the giant neurons of the caudal pontine reticular nucleus (PnC). Habituation is theorized to occur via hyperpolarizing big potassium (BK) channels localized at glutamatergic terminals of auditory afferents in the PnC. Prepulse inhibition is suggested to be mediated by cholinergic innervation of PnC giant neurons, with possible glutamate and/or GABA co-release. Animals were injected with Fluorogold at C3/C4 to label a subpopulation of PnC giant neurons, and following a startle experiment, brainstems were processed for pCREB expression. Using their respective markers, BK channels, glutamatergic, GABAergic, and cholinergic …

Revisiting Working Memory: Are Domain, Process And Global Models Mutually Exclusive, Nested Or Orthogonal?, Jeffrey P. Wong

Electronic Thesis and Dissertation Repository

Working memory (WM) is a cognitive function whereby task-relevant information is actively maintained and manipulated in mind for goal-directed behaviour. Three competing models, here dubbed the global, domain and process models, have attempted to explain its neural underpinnings. Despite extensive research however, no consensus has been reached. Here, we use two new WM paradigms to demonstrate that all three models are partially correct. In the first experiment, our results show that selected frontoparietal regions (MD), from the global model, are largely stimulus-independent. However, more posterior and caudal frontoparietal regions show stimulus-dependent activations as described by the domain model. In the …

Spatial And State-Dependent Effects Of Transcranial Magnetic Stimulation Of Prefrontal Cortex In Non-Human Primates, Chao Gu

Electronic Thesis and Dissertation Repository

The indirect effects of transcranial magnetic stimulation (TMS) within a distributed neural network are still largely unknown. Here we propose to use the non-human primate (NHP) oculomotor system as an animal model for investigating the effects of TMS. Across three animals, single pulses of TMS to the prefrontal cortex (PFC), including the frontal eye fields (FEF), reliably evoked a contralateral head turning synergy, similar to what is seen following intracortical microstimulation. Furthermore, double pulses of TMS paired with the memory-guided saccade paradigm only evoked neck muscle activity preceding contralateral saccades, showing similar state-dependency as previously observed in human TMS studies. …

Effects Of Resting State On Perceptual Learning, Sarah Eagleman Ph.D.

Dissertations & Theses (Open Access)

Psychophysical experiments in humans have demonstrated that improvements in perceptual learning tasks occur following daytime rests. The neural correlates of how rest influences subsequent sensory processing during these tasks remain unclear. One possible neural mechanism that may underlie this behavioral improvement is reactivation. Previously evoked network activity reoccurs – reactivates - in the absence of further stimulation. Reactivation was initially discovered in the hippocampus but has now been found in several brain areas including cortex. This phenomenon has been implicated as a general mechanism by which neural networks learn and store sensory information. However, whether reactivation occurs in areas relevant …

Fiber Pathways For Language In The Developing Brain: A Diffusion Tensor Imaging (Dti) Study, Iris J. Broce

FIU Electronic Theses and Dissertations

The present study characterized two fiber pathways important for language, the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) and the frontal aslant tract (FAT), and related these tracts to speech, language, and literacy skill in children five to eight years old. We used Diffusion Tensor Imaging (DTI) to characterize the fiber pathways and administered several language assessments. The FAT was identified for the first time in children. Results showed no age-related change in integrity of the FAT, but did show age-related change in the left (but not right) SLF/AF. Moreover, only the integrity of the right FAT was related to phonology but …

An Introduction To Drugs And The Neuroscience Of Behavior, Adam J. Prus

Books

This up-to-date text provides an introductory overview of the nervous system actions and behavioral effects of the major classes of psychoactive drugs, using pedagogy unique among pharmacology texts to make the topic approachable.

Variance Predicts Salience In Central Sensory Processing, Ann M. Hermundstad, John J. Briguglio, Mary M. Conte, Jonathan D. Victor, Vijay Balasubramanian, Gašper Tkačik

Publications and Research

Information processing in the sensory periphery is shaped by natural stimulus statistics. In the periphery, a transmission bottleneck constrains performance; thus efficient coding implies that natural signal components with a predictably wider range should be compressed. In a different regime—when sampling limitations constrain performance—efficient coding implies that more resources should be allocated to informative features that are more variable. We propose that this regime is relevant for sensory cortex when it extracts complex features from limited numbers of sensory samples. To test this prediction, we use central visual processing as a model: we show that visual sensitivity for local multi-point …

Dopaminergic And Activity-Dependent Modulation Of Mechanosensory Responses In Drosophila Melanogaster Larvae, Josh S. Titlow

Theses and Dissertations--Biology

A central theme of this dissertation is nervous system plasticity. Activity-dependent plasticity and dopaminergic modulation are two processes by which neural circuits adapt their function to developmental and environmental changes. These processes are involved in basic cognitive functions and can contribute to neurological disorder. An important goal in modern neurobiology is understanding how genotypic variation influences plasticity, and leveraging the quantitative genetics resources in model organisms is a valuable component of this endeavor. To this end I investigated activity-dependent plasticity and dopaminergic modulation in Drosophila melanogaster larvae using neurobiological and genetic approaches.

Larval mechanosensory behavior is described in Chapter 2. …

A Systems Biology Approach To Detect Eqtls Associated With Mirna And Mrna Co-Expression Networks In The Nucleus Accumbens Of Chronic Alcoholic Patients, Mohammed Mamdani

Theses and Dissertations

Alcohol Dependence (AD) is a chronic substance use disorder with moderate heritability (60%). Linkage and genome-wide association studies (GWAS) have implicated a number of loci; however, the molecular mechanisms underlying AD are unclear. Advances in systems biology allow genome-wide expression data to be integrated with genetic data to detect expression quantitative trait loci (eQTL), polymorphisms that regulate gene expression levels, influence phenotypes and are significantly enriched among validated genetic signals for many commonly studied traits including AD.

We integrated genome-wide mRNA and miRNA expression data with genotypic data from the nucleus accumbens (NAc), a major addiction-related brain region, of 36 …

Reportinfluence Of Emotional States On Inhibitory Gating: Animal Models To Clinical Neurophysiology, Howard Cromwell

Howard Casey Cromwell

tIntegrating research efforts using a cross-domain approach could redefine traditional constructs used inbehavioral and clinical neuroscience by demonstrating that behavior and mental processes arise not fromfunctional isolation but from integration. Our research group has been examining the interface betweencognitive and emotional processes by studying inhibitory gating. Inhibitory gating can be measured viachanges in behavior or neural signal processing. Sensorimotor gating of the startle response is a well-usedmeasure. To study how emotion and cognition interact during startle modulation in the animal model,we examined ultrasonic vocalization (USV) emissions during acoustic startle and prepulse inhibition. Wefound high rates of USV emission during the …