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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Error-related potentials and error awareness : A meta-analysis

De Temmerman, Karlien January 2023 (has links)
Performance monitoring is a crucial metacognitive function that allows for adaptive behaviour. Electrophysiological studies on error monitoring specifically, have shown how error trials in different tasks elicit two distinct signatures, the error-related negativity (ERN) and the error positivity (Pe). While studies find a robust relation between error awareness and the Pe, results regarding error awareness and the ERN are more divergent. Also, no agreement has been reached on the mechanisms that elicit these signals. This meta-analysis aims to explore the relation between these electrophysiological signatures and error awareness and how disparities in study design might explain divergent study results. Two meta-analyses were conducted and found a significant effect-size for error awareness on both the ERN and the Pe. Subgroup analyses were conducted to explore how different study-characteristics can influence these outcomes. Although no effects were found, these results remain mainly inconclusive since the number of included studies was very low, and their study designs quite similar.
102

Assessing the impact of textural selectivity and tactile sensitivity on eating behaviors

Andes, Amy Joy 30 September 2021 (has links)
No description available.
103

Electrophysiological Endophenotypes in Autism Spectrum Disorder: A Family Study

Clawson, Ann 01 June 2015 (has links) (PDF)
Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorder associated with altered neural connectivity and deficits in self-monitoring, response inhibition, and planning. One promising avenue of research to improve understanding of the symptoms and heritable nature of ASD may be the identification of neural endophenotypes of ASD. The error-related negativity (ERN) and post-error positivity (Pe), scalp-recorded event-related potentials (ERPs), reflect performance monitoring processes and may qualify as candidate endophenotypes of ASD. We collected ERP and behavioral data (error rates, response times) from 18 ASD probands and their families (mother, father, sibling) and 38 control youth and their parents to examine the utility of the ERN and Pe as endophenotypes of ASD. In order to examine differences based on group (ASD vs. control) and kinship (proband, sibling, mother, father), we conducted separate multiple regression analyses on behavioral and ERP data with group and kinship as predictors and families as clusters. We hypothesized that ASD probands would display reduced-amplitude ERN and impaired behavioral performance relative to control youth but no differences in Pe amplitude and that families of ASD probands would display reduced error minus correct (ΔERN) amplitudes and impaired behavioral performance relative to control families but no differences in ΔPe amplitude. We did not observe significant ERN amplitude group differences among ASD probands relative to control youth. Likewise, control youth did not differ from ASD probands on behavioral measures or Pe amplitudes. Analyses by family revealed that group and kinship did not significantly predict ΔERN amplitudes. However, fathers of ASD probands displayed significantly reduced ΔPe amplitudes relative to control fathers and parents displayed significantly larger ΔPe amplitudes and better performance than youth. Together, results do not provide sufficient evidence to support the ERN or Pe as an endophenotype or biomarker of ASD. These findings add to an overall heterogeneous literature on performance monitoring in ASD and point to the need for additional research to understand the state-related or trait-related factors that may contribute to ERN amplitudes in ASD.
104

Cross-Lingual Diphthong Perception: A Simultaneous EEG/fMRI Investigation

Sorensen, David Olonzo 01 November 2018 (has links)
Previous research indicates that humans develop a phonological library in infancy. As humans grow into adulthood, their phonological library becomes well established. Upon encountering phonemes from a new language, humans process these phonemes by comparison to their native phonological library. Event-related potentials (ERP), specifically the mismatch negativity, have been shown to indicate that this process of comparing non-native phonemes to our native phonological library is not improved through learning the new language as an adult. An alternative explanation may be that there is an underlying change in the neural generators as the non-native phonemes are learned, but that this change is not reflected in the ERP. The current study seeks to examine this hypothesis through the simultaneous collection of ERP and blood-oxygen-level-dependent functional MRI (fMRI) data. The findings of the ERP and fMRI data are inconclusive. The study also explores the processing of diphthongs, a category of phonemes rarely tested before, through both behavioral and neuroimaging methods. The study presents behavioral data demonstrating that non-native diphthongs are processed based upon the separate elements of the phonemes, rather than as complete units.
105

Mismatch Negativity Event Related Potential Elicited by Speech Stimuli in Geriatric Patients

Pierce, Dana Lynn 01 June 2019 (has links)
Hearing loss, as a result of old age, has been linked to a decline in speech perception despite the use of additional listening devices. Even though the relationship between hearing loss and decreased speech perception has been well established, research in this area has often focused on the behavioral aspects of language and not on the functionality of the brain itself. In the present study, the mismatch negativity, an event related potential, was examined in order to determine the differences in speech perception between young adult participants, geriatric normal hearing participants, and geriatric hearing-impaired participants. It was hypothesized that a significantly weaker mismatch negativity would occur in the geriatric hearing-impaired participants when compared to the young adult participants and the geriatric normal hearing participants. A passive same/different discrimination task was administered to 10 young adult controls (5 male, 5 female) and eight older adult participants with and without hearing loss (4 male, 4 female). Data from behavioral responses and event related potentials were recorded from 64 electrodes placed across the scalp. Results demonstrated that the mismatch negativity occurred at various amplitudes across all participants tested; however, an increased latency in the presence of the mismatch negativity was noted for the geriatric normal hearing and the geriatric hearing-impaired participants. Dipoles reconstructed from temporal event related potential data were located in the cortical areas known to be instrumental in auditory and language processing for the young adult participants; however, within the geriatric normal hearing and the geriatric hearing-impaired participants, dipoles were seen in multiple locations not directly associated with language and auditory processing. Although not conclusive, it appears that within the geriatric normal hearing and the geriatric hearing-impaired participants there is slower processing of the speech information, as well as some cognitive confusion which leads to fewer available resources for interpretation.
106

"A poem is a gesture toward home": Formal Plurality and Black/Queer Critical Hope in Jericho Brown's The Tradition

Hoelzer, Kaitlin 13 June 2022 (has links) (PDF)
Jericho Brown's The Tradition (2019), which won the Pulitzer Prize for poetry, includes four duplexes, a poetic form of Brown's own invention that combines the sonnet and the blues. Made of fourteen lines separated into seven couplets, the duplex is a complex structure comprised of sets of indents and repeated lines. Brown's use of disparate source forms to create a new form altogether challenges the supremacy of a singular, white American literary tradition, putting it into conversation with other traditions in order to critique its historically racist and heterosexist boundaries. As he does so, Brown works not to abolish "the tradition" or canon, but to expand it beyond reductive ideas of who and what is allowed into this historically exclusive space. The complexity of Brown's formal project mirrors the nuanced and critical hope the duplex form expresses and evokes in readers; in contrast to queer theory's long focus on negativity, Brown's duplexes align themselves with the work of José Muñoz and Mari Ruti, who assert that hope is equally as important as negativity, as they hold the positive and negative together in both form and content. The duplex seeks to expand emotional experience as well as the canon, ultimately attempting to change the way readers feel and act.
107

The Neural Correlates of Bad Timing: a Study on Error Related Negativity and the Human Metronome Task

Snellman, Henrik January 2023 (has links)
Whilst studies on rhythm-keeping and error-related negativity have been conducted, previous studies have given participants auditory or visual cues to indicate the rhythm they are meant to be maintaining. In this electroencephalography study, a novel experiment called the Human Metronome Task was introduced, using healthy university students as participants. The Human Metronome Task tested the participants by having them tap in synchrony with a beat, and then having the beat be removed, with the participants still being supposed to maintain the same beat with their taps, now without any auditory or visual aids. The purpose was to see if deviations in unassisted rhythm keeping are sufficient to elicit error-related negativity. When comparing different deviations of the tap-timing of each participant to their average tap-timing, no significant differences in electroencephalography amplitude were found. It was concluded that the Human Metronome Task is unable to elicit error-related negativity in participants. It seems plausible that this is due to the ambiguity of whether responses are erroneous or accurate. Thus, it seems as if it is necessary for more indications of whether a response is erroneous or not for the elicitation of error-related negativity than was present in the Human Metronome Task.
108

An asymmetry in the automatic detection of the presence or absence of a frequency modulation within a tone: a mismatch negativity study

Timm, Jana, Weise, Annekathrin, Grimm, Sabine, Schröger, Erich 27 July 2022 (has links)
The infrequent occurrence of a transient feature (deviance; e.g., frequency modulation, FM) in one of the regular occurring sinusoidal tones (standards) elicits the deviance related mismatch negativity (MMN) component of the event-related brain potential. Based on a memory-based comparison, MMN reflects the mismatch between the representations of incoming and standard sounds. The present study investigated to what extent the infrequent exclusion of an FM is detected by the MMN system. For that purpose we measured MMN to deviances that either consisted of the exclusion or inclusion of an FM at an early or late position within the sound that was present or absent, respectively, in the standard. According to the information-content hypothesis, deviance detection relies on the difference in informational content of the deviant relative to that of the standard. As this difference between deviants with FM and standards without FM is the same as in the reversed case, comparable MMNs should be elicited to FM inclusions and exclusions. According to the feature-detector hypothesis, however, the deviance detection depends on the increased activation of feature detectors to additional sound features. Thus, rare exclusions of the FM should elicit no or smaller MMN than FM inclusions. In passive listening condition, MMN was obtained only for the early inclusion, but not for the exclusions nor for the late inclusion of an FM. This asymmetry in automatic deviance detection seems to partly reflect the contribution of feature detectors even though it cannot fully account for the missing MMN to late FM inclusions. Importantly, the behavioral deviance detection performance in the active listening condition did not reveal such an asymmetry, suggesting that the intentional detection of the deviants is based on the difference in informational content. On a more general level, the results partly support the “fresh-afferent” account or an extended memory-comparison based account of MMN.
109

[pt] A NEGATIVIDADE DO POSITIVO: AFIRMAÇÃO E NEGAÇÃO EM DELEUZE / [en] THE NEGATIVITY OF THE POSITIVE: AFFIRMATION AND NEGATION IN DELEUZE

GABRIEL PRADO RODRIGUES 06 November 2020 (has links)
[pt] O presente trabalho tem por objetivo pensar o lugar do conceito de negatividade no interior da filosofia de Gilles Deleuze, frequentemente alcunhado como filósofo da afirmação. Conceitos como alegria e positividade foram utilizados na constituição de um cânone da alegria interpretativo, conforme a denominação de Andrew Culp, que confunde a primazia deleuziana da afirmação, como índice de univocidade ou imanência de uma diferença transcendental subjacente ao ser, com a exclusão irrestrita de todo elemento negativo de seu sistema. Nesse panorama, nossa pretensão é dupla: por um lado, partindo da definição geral do conceito deleuziano de univocidade, demonstrar de que modo as interpretações indicadas, ditas afirmacionistas, ao negligenciarem, em Deleuze, um sentido específico de negatividade, atinente ao seu conceito de criação, reproduzem um certo sentido de dogmatismo, enfaticamente criticado pelo autor. A figura tomada por Deleuze, nessas interpretações, arrisca ser, ela mesma, tornada mais um dos avatares do que o autor chamou de senso comum filosófico. Por outro lado, tentamos definir uma primeira forma de concepção dessa chamada negatividade, o que inclui esforços conceituais distintos. Primeiro, a exposição de leituras que também concebem, em Deleuze, espaço para o negativo; segundo, a tematização da relação entre Deleuze e Hegel, filósofo paradigmático da negatividade e objeto constante de críticas deleuzianas; terceiro, finalmente, a proposta de um conceito inicial de negatividade, oriundo da análise do que diz o autor, nomeadamente, sobre o termo. Um tal conceito deve basear-se no reconhecimento do primado ético da negação, enquanto vetor de orientação prática de um indivíduo situado do ponto de vista da atualidade do tempo presente, em oposição ao primado ontológico da afirmação, manifesto na compreensão da diferença como forma ou fundamento transcendental da experiência. / [en] The present work aims to think about the place of the concept of negativity within the philosophy of Gilles Deleuze, often nicknamed as a philosopher of affirmation. Concepts such as joy and positivity were used in the constitution of an interpretive canon of joy, according to Andrew Culp s denomination, which confuses Deleuzian primacy of afirmation, as an index of univocity or immanence of a transcendental difference underlying being, with an unrestricted exclusion of every negative element from his system. In this sense, our pretension is twofold: on the one hand, starting from the general definition of the concept of univocity, to demonstrate in which way the indicated interpretations, called affirmationists, by neglecting, in Deleuze, a specific sense of negativity related to his concept of creation, reproduce a certain sense of dogmatism, emphatically criticized by the author. The figure taken by Deleuze, in these interpretations, risks being itself made one of the avatars of what the author called philosophical common sense. On the other hand, we try to define a first way of conceiving this so-called negativity, what includes different conceptual efforts. First, an exhibition of readings that also conceive, in Deleuze, space for the negative; second, the thematization of the relationship between Deleuze and Hegel, the paradigmatic philosopher of negativity and constant object of Deleuzian criticism; third, finally, a proposal for an initial concept of negativity, derived from the analysis of what the author directly says regarding to the term. Such a concept must be based on the recognition of an ethical primacy of negation, comprehended as a vector for the practical orientation of an individual situated from the point of view of present time s actuality, as opposed to the ontological primacy of affirmation, manifest in the comprehension of difference as a transcendental form or foundation of experience.
110

EEG and fMRI studies of the effects of stimulus properties on the control of attention

Mugruza Vassallo, Carlos Andrés January 2015 (has links)
In this dissertation the effects of variations in stimulus properties and CTOA, in auditory attention tasks were explored using recently developed approaches to EEG analysis including LIMO. The last experiment was structured using information theory, designing an effective experiment. Four studies were carried out using a number parity decision task, that employed different combinations of cueing Tone (T), Novel (N) and the Goal (G) stimuli. In the first EEG study, contrary to previous findings (Polich 2002, 2007) in control participants, no correlation between the time of a novel condition to the next novel condition and P300 amplitude was found. Therefore single trial across-subject averaging of participants’ data revealed significant correlations (r > .3) of stimulus properties (such as probability, frequency, amplitude and duration) on P300, and even r > .5 was found when N was an environmental sound in schizophrenic patients. In the second EEG study, simultaneously with fMRI recordings, the participants that showed significant behavioural distraction evoked brain activations and differences in both hemispheres (similar to Corbetta, 2002, 2008) while the participants, as a whole, produced significant activations mainly in left cortical and subcortical regions. A context analysis was run in distracted participants contrasting the trials immediately prior to the G trials, resulting in different prefrontal activations, which was consistent with studies of prefrontal control of visual attention (Koechlin 2003, 2007). In the third EEG study, the distractor noise type was manipulated (white vs environmental sounds) as well as presence or absence of scanner background noise in a blocked design. Results showed consistent P300, MMN and RON due to environmental noise. In addition, using time constants found in MEG results (Lu, Williamson & Kaufman, 1992) and adding the CTOA to the analysis, an information theory framework was calculated. After the simulation of the information of the experiment, a saddle indentation in the curve of the information measure based on the states of the incoming signal at around 300 ms CTOA was found. This saddle indentation was evident in more than 60 novel trials. In the fourth study, the CTOA and stimulus properties were manipulated in a parametric experiment. Based on the three studies, reducing complexity if the task (first study), using more than 60 stimuli in the novel conditions (third study). The CTOA randomly varying between 250 ms or 500 ms. Thirty-eight ANCOVA with 2 categorical and 1 continuous regressors were conducted and determined which time and channels elicited reliably signatures (p <.05) in the whole participants at short CTOA. Results revealed differences for the waveforms of current condition by depending on which condition appeared previously as well in terms of frequency and duration in scalp frontal electrodes (such as the second study). These results were interpreted as a consequence of switching between modes of attention and alerting states which resulted in the activation of frontal areas. Moreover, contextual analyses showed that systematic manipulation of stimulus properties allowed the visualization of the relationships between CTOA, executive function and orienting of attention.

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