Blink waveform in electrooculogram (EOG) data was used to develop and adjust the method of drowsiness detection in drivers. The origins of some other waveforms in EOG signal were not very clearly understood. The purpose of this thesis work is to study the EOG signal and give explanation of different kind of waveforms in EOG signal, and give suggestions to improve the blink detection algorithm. The road driving test video records and synchronized EOG signal were used to build an EOG library. By comparing the video record of the driver’s face and the EOG data, the origin of the unknown waveforms were discovered and related with the driver’s behavior. Literature descriptions were given to explain the EOG signal. The EOG library is the main result of this project. It organized by different types of EOG signal. Description and explanation were given for each type of waveform, as well as some examples. The knowledge gained from the previous research review and the EOG library gives some improvement suggestions for the blink detection algorithm. These suggestions still need to be verified in practical way.

<p>For over 50 years, the Satisfaction of Search effect, and more recently known as the Subsequent Search Miss (SSM) effect, has plagued the field of radiology. Defined as a decrease in additional target accuracy after detecting a prior target in a visual search, SSM errors are known to underlie both real-world search errors (e.g., a radiologist is more likely to miss a tumor if a different tumor was previously detected) and more simplified, lab-based search errors (e.g., an observer is more likely to miss a target ‘T’ if a different target ‘T’ was previously detected). Unfortunately, little was known about this phenomenon’s cognitive underpinnings and SSM errors have proven difficult to eliminate. However, more recently, experimental research has provided evidence for three different theories of SSM errors: the Satisfaction account, the Perceptual Set account, and the Resource Depletion account. A series of studies examined performance in a multiple-target visual search and aimed to provide support for the Resource Depletion account—a first target consumes cognitive resources leaving less available to process additional targets. </p><p>To assess a potential mechanism underlying SSM errors, eye movements were recorded in a multiple-target visual search and were used to explore whether a first target may result in an immediate decrease in second-target accuracy, which is known as an attentional blink. To determine whether other known attentional distractions amplified the effects of finding a first target has on second-target detection, distractors within the immediate vicinity of the targets (i.e., clutter) were measured and compared to accuracy for a second target. To better understand which characteristics of attention were impacted by detecting a first target, individual differences within four characteristics of attention were compared to second-target misses in a multiple-target visual search. </p><p>The results demonstrated that an attentional blink underlies SSM errors with a decrease in second-target accuracy from 135ms-405ms after detection or re-fixating a first target. The effects of clutter were exacerbated after finding a first target causing a greater decrease in second-target accuracy as clutter increased around a second-target. The attentional characteristics of modulation and vigilance were correlated with second- target misses and suggest that worse attentional modulation and vigilance are predictive of more second-target misses. Taken together, these result are used as the foundation to support a new theory of SSM errors, the Flux Capacitor theory. The Flux Capacitor theory predicts that once a target is found, it is maintained as an attentional template in working memory, which consumes attentional resources that could otherwise be used to detect additional targets. This theory not only proposes why attentional resources are consumed by a first target, but encompasses the research in support of all three SSM theories in an effort to establish a grand, unified theory of SSM errors.</p> / Dissertation

Emotional eating behavior is characterized by eating a large amount of calorie dense sweet and/or high fat foods in an attempt to control, cope with, or avoid negative emotions. Numerous factors are likely to contribute to emotional eating behavior, including attentional factors, such as rumination and avoidance coping. Rumination based emotional eating (attention focused on negative stimuli while mindlessly eating) is often utilized to improve mood while dwelling on problems. However, for those inclined to escape/avoid troublesome thoughts, another type of emotional-eating pattern may be used. By focusing attention on food, emotional eating is believed to distract individuals from negative emotions. However, along with avoiding distressing thoughts, a strong attentional focus on food may also lead to diminished attention resources and subsequently the missing of self-preserving thoughts (e.g. dietary restraint or satiety). While Denke & Lamm (2015) explored neural mechanisms underlying rumination based emotional eating, to the best of our knowledge, no one has investigated the neural correlates underlying avoidance based emotional eating. This study examined how attentional sub-processes contribute to emotional eating behavior among female participants in a task designed to explore escape type emotional-eating behavior. Dense-array EEG and a version of the canonical attentional blink task were used to ascertain the neural correlates underlying the attentional sub-processes and how attentional activation differs for emotional eaters vs. non-emotional eaters. Findings do not support the food fixation escape type emotional-eater hypothesis, but do indicate task validity.

abstract: During attempted fixation, the eyes are not still but continue to produce so called "fixational eye movements", which include microsaccades, drift, and tremor. Microsaccades are thought to help prevent and restore vision loss during fixation, and to correct fixation errors, but how they contribute to these functions remains a matter of debate. This dissertation presents the results of four experiments conducted to address current controversies concerning the role of microsaccades in visibility and oculomotor control. The first two experiments set out to correlate microsaccade production with the visibility of foveal and peripheral targets of varied spatial frequencies, during attempted fixation. The results indicate that microsaccades restore the visibility of both peripheral targets and targets presented entirely within the fovea, as a function of their spatial frequency characteristics. The last two experiments set out to determine the role of microsaccades and drifts on the correction of gaze-position errors due to blinks in human and non-human primates, and to characterize microsaccades forming square-wave jerks (SWJs) in non-human primates. The results showed that microsaccades, but not drifts, correct gaze-position errors due to blinks, and that SWJ production and dynamic properties are equivalent in human and non-human primates. These combined findings suggest that microsaccades, like saccades, serve multiple and non-exclusive functional roles in vision and oculomotor control, as opposed to having a single specialized function. / Dissertation/Thesis / Doctoral Dissertation Neuroscience 2014

This report discusses the accuracy of blink detection in eye tracking, using machine learningalgorithms. Blink detection is used in a wide variety of medicinal and psychological applica-tions such as a controller for motor impaired individuals. Image classification has recentlybeen used in eye tracking and blink detection applications. The blink detection is appliedon data captured from the Pupil Invisible head-mounted eye tracker. The aim is that givenan image, the classifier can accurately determine the state of which the eye is in, blink oropen.These tests will be conducted on two SVM (support vector machine) models using differenttraining data, one trained on data from controlled environments, the other model also trainedon uncontrolled environments. For this project, data was captured in infrared disturbedenvironments to see how it affects the models performance. These models are evaluatedaccording to their accuracy using multiple different metrics. This rapport will discuss theresults of both classifiers in both tests, in addition to describing training methodology withan aim to find if blink detection is viable in infrared disturbed environments.

The attentional blink occurs when detection of a second target (T2) is impaired when it occurs between 180 to 450 ms after the first target (T1) in a rapid serial visual presentation (RSVP). The attentional blink can be affected by relevant emotional stimuli, like emotional faces, such that an emotional T1 enhances the attentional blink, and an emotional T2 attenuates it. However, not all studies use the same type of face stimuli, and there is debate over whether schematic and photo-realistic faces are processed in the same way. Furthermore, the effect of emotion on the attentional blink should differ with age, given the tendency for younger adults to display a negativity bias and for older adults to display a positivity effect. Very little research has been conducted on the attentional blink with emotional stimuli in older adults. In fact, the effect of emotional faces, which are arguably more salient stimuli than other stimuli such as emotional words, on the attentional blink has not been investigated in older adults. Therefore, this study sought to examine the impact of emotional faces on the attentional blink in younger and older adults using photo-realistic faces with angry, happy, and neutral expressions as targets in a RSVP. Although older adults did perform worse overall, there were no age differences in the effect of emotion on the attentional blink. Angry faces, as well as happy faces to a limited extent, increased the attentional blink when they served as T1. Neither the angry or happy faces as T2 were able to attenuate the blink. Given that emotional faces affected the attentional blink at T1 but not at T2, it may be the case that the emotional expressions served to maintain attention, rather than to capture it. Future studies are necessary to test this idea, as well as to more directly test the differential effect of emotional photorealistic and schematic faces on the attentional blink.

Advances in Human Computer Interface (HCI) have made this area of research important for improving the standard of living for people with disabilities. An eye blink system is presented to allow people with disabilities to control a standard computer mouse. This system is designed for people who are paralytic with no control over their arms, speech, and anyone who is restricted to only the control of eye and head movements. This system is based on infrared reflectivity to capture and analyze real time eye blink signal of the user. It uses simple economical hardware electronics to emulate the functionality of computer mouse click based on user eye blinks. Informal tests show that the system can successfully distinguish between voluntary and involuntary eye blinks and can emulate user mouse clicks. This interface offers an economical, non-invasive, hands-free, plug and play device that provides the disabled with flexibility to improve their quality of life.

This study examined how attentional sub-processes contribute to binge-eating. Dense-array EEG and a version of the canonical attentional blink task were used to ascertain the neural correlates underlying the attentional sub-processes that comprise the Posner model of attention (alerting, orienting, and executive control) and how attentional activation differs for binge-eaters vs. non-binge eaters. Furthermore, we examined a number of the event-related potentials (ERP), including P2 activation, which has been linked with orientating of attention, and N2 activation which has been linked with attentional conflict. We found decreased P2 activation for binge-eaters, in the negative condition, for incorrect target 2 (T2) detection trials. We also found more N2 activation for binge-eaters than non-binge eaters, in negative trials when T2 was not detected. This pattern of results suggest that binge-eaters showed deficiencies in allocating attention to stimuli that followed negative images; this attention deficiency may be a key factor for binge-eating behavior.

Orientador: Luiz Antonio de Lima Resende / Resumo: Introdução: O reflexo trigêmino-facial (RTF) pode ser estudado e mensurado através de técnica eletrofisiológica - o Blink Reflex. As respostas R2 são integradas em nível ponto-bulbar por neurônios que têm relação anatômica e funcional com a formação reticular, por sua vez relacionada à fisiologia do sono e fisiopatologia da Síndrome da Apneia Obstrutiva do Sono (SAOS). Objetivo: Estudar o RTF em pacientes com SAOS e correlacionar os achados com parâmetros polissonográficos. Métodos: Foram estudados 50 pacientes adultos com SAOS, de ambos os sexos, submetidos à polissonografia, estudos de condução nervosa sensitiva e motora nos membros, e estudo do RTF. Resultados: Dos 50 pacientes estudados, 10 preencheram critérios de exclusão. Dentre 40 pacientes analisados, o RTF foi normal em 7, mostrou achados de hiperexcitabilidade em 16 (grande amplitude, longa duração e/ou curta latência) - Grupo 1, e achados de hipoexcitabilidade em 17 (baixa amplitude e/ou latência prolongada ou resposta ausente) - Grupo 2, com diferenças estatisticamente significativas entre os grupos (p < 0.0001). As alterações do RTF não apresentaram correlações estatisticamente significativas com os diferentes parâmetros polissonográficos estudados. Conclusões: A avaliação eletrofisiológica do RTF permitiu separar pacientes com SAOS em 3 grupos (normal, achados de hiperexcitabilidade, achados de hipoexcitabilidade) evidenciando normalidade, disfunção e/ou lesão de grupos neuronais do tronco encefálico. / Doutor

Submitted by THIAGO DIAS FERNANDES null (thiagodf83@hotmail.com) on 2017-02-03T21:14:57Z No. of bitstreams: 1 TESE PRONTA FINAL.pdf: 8515287 bytes, checksum: dedec31a9ce185e261cf9657fdb3dd34 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-07T12:44:46Z (GMT) No. of bitstreams: 1 fernandes_td_dr_bot.pdf: 8515287 bytes, checksum: dedec31a9ce185e261cf9657fdb3dd34 (MD5) / Made available in DSpace on 2017-02-07T12:44:46Z (GMT). No. of bitstreams: 1 fernandes_td_dr_bot.pdf: 8515287 bytes, checksum: dedec31a9ce185e261cf9657fdb3dd34 (MD5) Previous issue date: 2016-12-05 / Introdução: O reflexo trigêmino-facial (RTF) pode ser estudado e mensurado através de técnica eletrofisiológica - o Blink Reflex. As respostas R2 são integradas em nível ponto-bulbar por neurônios que têm relação anatômica e funcional com a formação reticular, por sua vez relacionada à fisiologia do sono e fisiopatologia da Síndrome da Apneia Obstrutiva do Sono (SAOS). Objetivo: Estudar o RTF em pacientes com SAOS e correlacionar os achados com parâmetros polissonográficos. Métodos: Foram estudados 50 pacientes adultos com SAOS, de ambos os sexos, submetidos à polissonografia, estudos de condução nervosa sensitiva e motora nos membros, e estudo do RTF. Resultados: Dos 50 pacientes estudados, 10 preencheram critérios de exclusão. Dentre 40 pacientes analisados, o RTF foi normal em 7, mostrou achados de hiperexcitabilidade em 16 (grande amplitude, longa duração e/ou curta latência) - Grupo 1, e achados de hipoexcitabilidade em 17 (baixa amplitude e/ou latência prolongada ou resposta ausente) - Grupo 2, com diferenças estatisticamente significativas entre os grupos (p < 0.0001). As alterações do RTF não apresentaram correlações estatisticamente significativas com os diferentes parâmetros polissonográficos estudados. Conclusões: A avaliação eletrofisiológica do RTF permitiu separar pacientes com SAOS em 3 grupos (normal, achados de hiperexcitabilidade, achados de hipoexcitabilidade) evidenciando normalidade, disfunção e/ou lesão de grupos neuronais do tronco encefálico. / Background: The Blink Reflex can be evaluated through electrophysiological method. The R2 late responses are mediated by neuronal groups in the pons and medulla with anatomical and physiological relation with the reticular formation, wich is related to sleep physiology and physiopathology of the Obstructive Sleep Apnea (OSA). Objective: To study the Blink Reflex in patients with OSA and to correlate the findings with polysomnographic parameters. Methods: Fifty adult patients with OSA diagnosis were enrolled for polysomnography, limb conduction studies and Blink Reflex. Results: Ten patients fulfilled exclusion criteria. From 40 patients studied, 7 showed normal Blink Reflex, 16 hyperexcitability findings (high amplitude, long duration, and/or short latency response) - Group 1, and 17 hypo excitability findings (low amplitude and/or prolonged latency, or absent response) - Group 2, with significant differences between groups (p < 0.0001). No statistically significant difference was observed between the Blink Reflex abnormalities and the polysomnographic parameters evaluated. Conclusion: The electrophysiological evaluation of the blink reflex afforded to distinguish OSA patients in 3 groups (normal, hyperexcitability findings, hypo excitability findings) related to normality, dysfunction and/or injury of neuronal groups in the brainstem.