Browsing by Subject "priming"

Now showing 1 - 4 of 4
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    Cortical Processing of Phonetic and Emotional Information in Speech: A Cross-Modal Priming Study
    (2015-05) Diamond, Erin
    The present study utilized a cross-modal priming paradigm to investigate dimensional information processing in speech. Primes were facial expressions that varied in two dimensions: affect (happy, neutral, or angry) and mouth shape (corresponding to either /a/ or /i/ vowels). Targets were CVC words that varied by prosody and vowel identity. In both the phonetic and prosodic conditions, adult participants responded to congruence or incongruence of the visual-auditory stimuli. Behavioral results showed a congruency effect in percent correct and reaction time measures. Two ERP responses, the N400 and late positive response, were identified for the effect with systematic between-condition differences. Localization and time-frequency analyses indicated different cortical networks for selective processing of phonetic and emotional information in the words. Overall, the results suggest that cortical processing of phonetic and emotional information involves distinct neural systems, which has important implications for further investigation of language processing deficits in clinical populations.
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    Metabolomics study on Arabidopsis thaliana abiotic stress responses for priming, recovery, and stress combinations
    (2018-04) Xu, Yuan
    Temperature, water, and light are three stress factors that have major influences on plant growth, development, and reproduction. Plants can be primed to an acclimated state by a prior mild stress to enhance their resistance to future stress. ‘Priming’ is related to plant stress ‘memory’ during recovery. Plants may need to balance between keeping the memory for enhanced stress defense and resetting for maximum growth and development during recovery. In the field, plants are more often to encounter a combination of different abiotic stresses rather than a specific single stress condition. Plant responses to a combination of stresses may exhibit quite unique defense and acclimation responses as compared to the response elicited by each individual stress, which should not be simply considered as the sum of the two different stresses. However, the simultaneous occurrence of multiple stress events is rarely studied experimentally, especially by metabolomics methods. Metabolomics, the comprehensive, quantitative and qualitative analysis of small molecules, is an emerging 'omics' platform that is an important next-generation systems biology approach. By providing an instantaneous “snapshot” of metabolic processes that occur in an organism, metabolomics can potentially provide insightful molecular mechanism information to questions about physiological function in complex biological systems. The objective of this thesis research was to use both untargeted and targeted metabolomics approaches to investigate plant shared and unique metabolic features in responses to single as well as multiple abiotic stresses, the priming effect of temperature stresses, plant memory during recovery phase, and the relationships between combined stress with each of individual stresses. An ultra-high pressure liquid chromatography-high resolution mass spectrometry (UHPLC-HR-MS)-based metabolomics approach was utilized. In chapter two, a metabolomics study on Arabidopsis thaliana 11-day-old seedling’s abiotic stress responses including heat (basal and acquired), cold (basal and acquired), drought and high light with 2-day-recovery was performed using a standardized reference system. In chapter three, Arabidopsis thaliana 11-day-old seedlings that were induced by the combination of different abiotic stresses including heat, cold, drought, salinity, and high light, that mimics field environment was studied. From this thesis research, a number of potential stress signatures determined from the untargeted analysis were identified, quantified and clustered by stress response patterns. Central metabolism were found to undergo a complex regulatory process in response to stress. Shared and unique metabolic signatures were identified across different abiotic single and combined stresses. The majority of stress signatures clustered together and exhibited shared response patterns. However, cysteine, glutathione, and maltose showed unique and dramatic patterns, demonstrating large changes in glutathione biosynthesis, glutathione oxidation, and starch degradation. The results showed that only two combined stresses, including high light x cold and cold x salinity, had metabolic effects that reflected both of their constituent single stresses. Most combined stresses had one dominant stress that had a defining impact on the plant metabolic profile. Drought stress is the dominant stress for all of its stress combinations. Two combined stresses, including high light x heat and high light x salinity, showed unique metabolic stress response patterns that are not similar to any of their individual stresses. Most of these metabolic features were specifically changed only in the combined stress, which should thus be considered as novel stress conditions. In summary, this work utilized metabolomics to study plant priming effects, recovery processes, and combined stress responses. It led to an improved understanding of how plants respond to abiotic stresses and may support subsequent studies on plant abiotic stress metabolic flux analyses.
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    Optimization of Repetitive Transcranial Magnetic Stimulation With Priming In Chronic Stroke
    (2014-12) Cassidy, Jessica
    Purpose: Stroke is leading cause of long-term disability in the United States. The direct destruction of neural tissue from stroke combined with imbalances in transcallosal-mediated interhemispheric inhibition complicate motor recovery. Repetitive transcranial magnetic stimulation (rTMS) is thought to condition surviving but dormant neurons in the ipsilesional primary motor cortex (M1) region to become more amenable to voluntary recruitment during affected extremity movement. Low-frequency rTMS suppresses hyperexcitability in the contralesional hemisphere which can "disinhibit" the ipsilesional hemisphere resulting in greater ipsilesional M1 excitability. A bout of high-frequency excitatory rTMS, referred to as priming, potentiates the suppressive effects of low-frequency rTMS in healthy individuals. The objective of this study was to compare changes in brain excitability and affected hand function following three different rTMS treatments to ascertain whether potential gains from priming stimulation translate to the stroke brain. Methods: Eleven adults (3 females, mean age ± SD = 66 ± 9.4 years) with chronic stroke received three treatments (active 6-Hz priming + active 1-Hz rTMS, active 1-Hz priming + active 1-Hz rTMS, and sham 6-Hz priming + active 1-Hz rTMS) to contralesional M1 in random order over a five-week course with a one-week washout period between treatments. Cortical excitability including interhemispheric inhibition, short-interval intracortical inhibition, intracortical facilitation, and cortical silent period measures along with affected hand function were analyzed using a mixed effects linear model. The model checked for carryover, treatment-by-period interactions, and baseline differences before analyzing within- and between-treatment differences from baseline. Results: Active 6-Hz primed 1-Hz rTMS produced significant within-treatment differences in short-interval intracortical inhibition and cortical silent period duration from baseline indicating reduced intracortical inhibition. Compared to active 1-Hz and sham 6-Hz primed 1-Hz rTMS, active 6-Hz priming generated significantly greater decreases in cortical silent period duration. Discussion: The utility of priming in stroke does not present in such a straightforward manner as it does in healthy individuals given that active 6-Hz priming did not potentiate all outcome measures. Several potential factors are discussed. Our significant findings support the existence of `synaptic wisdom' in the stroke brain involving the deployment of homeostatic and/or metaplastic processes that preserve synaptic function.
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    The Priming Effect of Price Display and Banner Advertising on Online Consumers’ Price Sensitivity
    (2020-08) You, Jiye
    This study drew from priming literature to explore under-investigated factors that contribute to online consumers’ price sensitivity and the subsequent brand interest. Specifically, it examined how being exposed to price cues on brand websites makes it easier to retrieve the price concept in a subsequent task (increased fluency), which in turn results in a higher valuation of the price attribute (higher price importance). Three pretests were conducted to develop the visual stimuli that were used in the main study and for the manipulation check of each variable. In the main study, participants were assigned to one of the conditions in a 3 (price cue: no price cue vs. small price cue vs. large price cue) x 2 (awareness: aware vs. unaware) x 2 (luxuriousness: mass vs. luxury) between-subjects study design and were exposed to the corresponding image of a mock retail website. A 3x2x2 ANOVA and a simple mediation analysis were conducted to examine each part of the conceptual model, and the entire model was tested using a moderated serial mediation. The results suggest that presenting the price of the product under examination (a price cue in the aware condition), compared to not presenting the price, increased the accessibility of the price concept, resulting in higher price sensitivity. In contrast, presenting a banner advertisement with the price of an irrelevant product (a price cue in the unaware condition), compared to presenting a banner advertisement without the price, decreased the accessibility of the price concept, resulting in lower price sensitivity. The lower price sensitivity led to higher brand interest. Implications of these results were discussed in the context of other studies.