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.

Σκοπός της παρούσας Διπλωματικής Εργασίας είναι η ανάπτυξη και εφαρμογή τεχνικών ψηφιακής επεξεργασίας εικόνων για τον εντοπισμό του οφθαλμού και τον υπολογισμό συγκεκριμένων παραμέτρων που συνδέονται με την κατάσταση του χρήστη. Συγκεκριμένα, χρησιμοποιήθηκε ένα ολοκληρωμένο Σύστημα Εντοπισμού Οφθαλμού που περιλαμβάνει τα υποσυστήματα της CMOS κάμερα, της μεταφοράς δεδομένων – εικόνων, της ψηφιοποίησης των δεδομένων, και τέλος το υποσύστημα της επεξεργασίας εικόνων οφθαλμού και του υπολογισμού παραμέτρων. Στα πλαίσια του τελευταίου αυτού υποσυστήματος αναπτύχθηκαν δύο μεθοδολογίες που βασίστηκαν στην εφαρμογή αλγορίθμων ψηφιακής επεξεργασίας εικόνων. Η πρώτη μεθοδολογία βασίστηκε στον υπολογισμό της μέσης φωτεινότητας για την άνω και την κάτω περιοχή του οφθαλμού. Η χρονική μεταβολή των δύο τιμών της φωτεινότητας χρησιμοποιήθηκε για την εξαγωγή πληροφοριών για την κατάσταση του οφθαλμού (ανοιχτός ή κλειστός). Η δεύτερη μεθοδολογία στηρίχτηκε σε ένα συνδυασμό τεχνικών ψηφιακής επεξεργασίας εικόνων. Η επεξεργασία κάθε εικόνας της ακολουθίας video περιλαμβάνει τέσσερα βασικά βήματα: (α) ευθυγράμμιση της εικόνας σε σχέση με ένα κοινό σύστημα αναφοράς, (β) εφαρμογή δύο φίλτρων για την ανίχνευση των κορυφών και των κοιλάδων της εικόνας, (γ) σύντηξη των δύο φιλτραρισμένων εικόνων που προκύπτουν και (δ) μετατροπή της εικόνας σύντηξης σε δυαδική με εφαρμογή κατάλληλου κατωφλίου. Η καταμέτρηση των λευκών εικονοστοιχείων της δυαδικής εικόνας στην περιοχή του οφθαλμού καθορίζει την κατάσταση του οφθαλμού (ανοικτός ή κλειστός). Τέλος, και μέσω του λογισμικού, υπολογίζονται οι σχετικές παράμετροι της κατάστασης του οφθαλμού όπως ο αριθμός ανοιγο-κλεισίματος οφθαλμού, η διάρκεια κάθε ανοιγο-κλεισίματος οφθαλμού και οι χρονικές αποστάσεις μεταξύ των προσδιορισμένων ανοιγο-κλεισιμάτων σε μια αλληλουχία συλλεγμένων εικόνων. / The scope of the thesis was the development and application of digital image processing techniques in order to detect human eye in video sequences and determine parameters related to the user’s state. Specifically, an integrated Eye-Tracking System was used in order to obtain the necessary image frames for further processing. The System consists of four modules, the CMOS camera module, the transfer module, the digitization module and the software module. The software module was based on the application of image processing techniques to detect the eye and calculate specific parameters. Two image processing techniques were developed and tested throughout this thesis. The first method was based on the calculations of the mean brightness of the upper and lower eye region for each frame of the video sequence. The temporal variation of this mean value provided useful information for the eye state (open/closed). The second method was based on a combination of various image processing techniques. The processing of each video frame comprises of four basic steps: a) registration of the image in relation to the first frame of the video sequence, b) filtering in order to detect the peaks and valleys of the image being processed, c) fusion of the filtered images, and d) binarization of the fused image by thresholding. The calculation of the number of white pixels in the eye region of the binary image indicates the state of the eye (open/closed) and allows the determination of the blink parameters related to the user’s state (vigilance/somnolence). The parameters being measured throughout this thesis were the number of eye blinks, the blink duration and the blink interval.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Muscular dystrophy, spinal cord injury, or amyotrophic lateral sclerosis (ALS) are injuries and disorders that disrupts the neuromuscular channels of the human body thus prohibiting the brain from controlling the body. Brain computer interface (BCI) allows individuals to bypass the neuromuscular channels and interact with the environment using the brain. The system relies on the user manipulating his neural activity in order to control an external device. Electroencephalography (EEG) is a cheap, non-invasive, real time acquisition device used in BCI applications to record neural activity. However, noise, known as artifacts, can contaminate the recording, thus distorting the true neural activity. Eye blinks are a common source of artifacts present in EEG recordings. Due to its large amplitude it greatly distorts the EEG data making it difficult to interpret data for BCI applications. This study proposes a new combination of techniques to detect and correct eye blink artifacts to improve the quality of EEG for BCI applications. Independent component analysis (ICA) is used to separate the EEG signals into independent source components. The source component containing eye blink artifacts are corrected by detecting each eye blink within the source component and using a trained wavelet neural network (WNN) to correct only a segment of the source component containing the eye blink artifact. Afterwards, the EEG is reconstructed without distorting or removing the source component. The results show a 91.1% detection rate and a 97.9% correction rate for all detected eye blinks. Furthermore for channels located over the frontal lobe, eye blink artifacts are corrected preserving the neural activity. The novel combination overall reduces EEG information lost, when compared to existing literature, and is a step towards improving EEG pre-processing in order to provide cleaner EEG data for BCI applications. / AFRIKAANSE OPSOMMING: Spierdistrofie, ’n rugmurgbesering, of amiotrofiese laterale sklerose (ALS) is beserings en steurnisse wat die neuromuskulêre kanale van die menslike liggaam ontwrig en dus verhoed dat die brein die liggaam beheer. ’n Breinrekenaarkoppelvlak laat toe dat die neuromuskulêre kanale omlei word en op die omgewing reageer deur die brein. Die BCI-stelsel vertrou op die gebruiker wat sy eie senuwee-aktiwiteit manipuleer om sodoende ’n eksterne toestel te beheer. Elektro-enkefalografie (EEG) is ’n goedkoop, nie-indringende, intydse dataverkrygingstoestel wat gebruik word in BCI toepassings. Nie net senuwee aktiwiteit nie, maar ook geraas , bekend as artefakte word opgeneem, wat dus die ware senuwee aktiwiteit versteur. Oogknip artefakte is een van die algemene artefakte wat teenwoordig is in EEG opnames. Die groot omvang van hierdie artefakte verwring die EEG data wat dit moeilik maak om die data te ontleed vir BCI toepassings. Die studie stel ’n nuwe kombinasie tegnieke voor wat oogknip artefakte waarneem en regstel om sodoende die kwaliteit van ’n EEG vir BCI toepassings te verbeter. Onafhanklike onderdeel analise (Independent component analysis (ICA)) word gebruik om die EEG seine te skei na onafhanklike bron-komponente. Die bronkomponent wat oogknip artefakte bevat word reggestel binne die komponent en gebruik ’n ervare/geoefende golfsenuwee-netwerk om slegs ’n deel van die komponent wat die oogknip artefak bevat reg te stel. Daarna word die EEG hervorm sonder verwringing of om die bron-komponent te verwyder. Die resultate toon ’n 91.1% opsporingskoers en ’n 97.9% regstellingskoers vir alle waarneembare oogknippe. Oogknip artefakte in kanale op die voorste lob word reggestel en behou die senuwee aktiwiteit wat die oorhoofse EEG kwaliteit vir BCI toepassings verhoog.

The voltage gated potassium channel Kv1.2 plays a key role in the central nervous system and mutations in Kv1.2 cause neurological disorders such as epilepsies and ataxias. In the cerebellum, regulation of Kv1.2 is coupled to learning and memory. We have previously shown that blocking Kv1.2 by infusing its specific inhibitor tityustoxin-kα (TsTX) into the lobulus simplex of the cerebellum facilitates eyeblink conditioning (EBC) and that EBC itself modulates Kv1.2 surface expression in cerebellar interneurons. The metabotropic glutamate receptor mGluR1 is required for EBC although the molecular mechanisms are not fully understood. Here we show that infusion of the mGluR1 agonist (S)-3,5-dihydroxyphenylglycine (DHPG) into the lobulus simplex of the cerebellum mimics the facilitating effect of TsTX on EBC. We therefore hypothesize that mGluR1 could act, in part, through suppression of Kv1.2. Earlier studies have shown that Kv1.2 suppression involves channel tyrosine phosphorylation and endocytocytic removal from the cell surface. In this study we report that an excitatory chemical stimulus (50mM K+-100µM glutamate) applied to cerebellar slices enhanced Kv1.2 tyrosine phosphorylation and that this increase was lessened in the presence of the mGluR1 inhibitor YM298198. More direct evidence for mGluR1 modulation of Kv1.2 comes from our finding that selective activation of mGluR1 with DHPG reduced the amount of surface Kv1.2 detected by cell surface biotinylation in cerebellar slices. To determine the molecular pathways involved we used an unbiased mass spectrometry-based proteomics approach to identify Kv1.2-protein interactions that are modulated by mGluR1. Among the interactions enhanced by DHPG were those with PKC-γ, CaMKII, and Gq/G11, each of which had been shown in other studies to co-immunoprecipitate with mGluR1 and contribute to its signaling. Of particular note was the interaction between Kv1.2 and PKC-γ since in HEK cells and hippocampal neurons Kv1.2 endocytosis is elicited by PKC activation. We found that activation of PKCs with PMA reduced surface Kv1.2, while the PKC inhibitor Go6983 attenuated the reduction in surface Kv1.2 levels elicited by DHPG and PMA, suggesting that the mechanism by which mGluR1 modulates cerebellar Kv1.2 likely involves PKC. mGluR1 has been shown to signal independently of the agonist through a constitutively active, protein kinase A-dependent pathway in the cerebellum. Using HEK293 cells we show that co-expression of mGluR1 increases the surface expression levels of Kv1.2. This effect occurs in absence of mGluR1 agonists and in the presence of a noncompetitive mGluR1 inhibitor YM298198. Co-expression of known downstream effectors of the agonist driven mGluR1 pathway such as PKC-γ, CaMKIIα, Grid2 had no effect on Kv1.2 surface expression or on the ability of mGluR1 agonist to modulate that expression. In contrast, the inverse agonist BAY 36-7620 significantly reduced the mGluR1 effect on Kv1.2 surface expression, as did pharmacological inhibition of PKA with KT5720. Therefore, mGluR1 is involved in regulation of surface Kv1.2 via dual mechanisms, the agonist dependent mechanism reduces surface Kv1.2 via PKC, while agonist independent constitutive mechanism increases surface Kv1.2 via PKA.

This master thesis deals with the issues of the eye blink recognition from video. The main task is to analyse algorithms dealing with a detection of persons and make a program that could recognize the eye blink. Analysis of these algorithms and their problems are in the first part of this thesis. In the second part design and properties of my program are described. The realization of the program is based on the method of move detection using the accumulated difference frame, which helps to identify the eye areas. The eye blink detection algorithm tests a match between a tresholded pattern of the eye area taken from the actual frame and the frame before. The resolution whether the eye blink happened or not, is based on the level of the match. The algorithm is designed for watching a sitting man, which is slightly moving. The background can be a little dynamic as well. An average quality video with a moderator and dynamic backround was used as a tested subject.

As humans age, the attenuation of dopamine and norepinephrine neuromodulation in the fronto-striatal network could lead to deficits in decision-making and reward learning. However, the questions about the nature of how age-related decline in the dopamine and norepinephrine systems may alter decision-making and reward learning are not well understood. This doctoral dissertation used a multimodal approach to investigate the contributions of dopamine and norepinephrine in decision-making and reward learning in old age. The first study of this dissertation focused on how age-related decline in the norepinephrine system may affect anticipatory values and reward prediction errors during reward learning. Specifically, a probabilistic decision-making task was conducted, and a reinforcement Q-learning model was applied to investigate anticipatory values of choice options for each trial and individual’s value sensitivity. Potential psychophysiological proxies of norepinephrine functioning, such as task-related pupillary responses and locus coeruleus structural integrity, were assessed in younger and older adults. Results showed that after the choice options and feedback were shown, younger adults’ pupil dilations negatively correlated with anticipatory values, suggesting uncertainty about outcome probabilities. However, this effect was smaller in the choice phase and absent in the feedback phase in older adults, indicating impairments in value estimation and updating in old age. Although older adults showed a lower locus coeruleus integrity than younger adults, which might indicate reduced norepinephrine functioning, individual’s value sensitivity was only associated with task-related pupil dilations but not with locus coeruleus integrity. The second study investigated whether increasing the saliency of specific information of choice options may improve older adults’ decision performance during value-based decision-making and what the mechanisms of increasing information saliency could be. In particular, the saliency of outcome probabilities was highlighted using a color-coding scheme as a decision-aid in a mixed lottery choice task. Spontaneous eye-blink rate and pupillary responses were measured in younger and older adults as potential proxies of dopamine and norepinephrine functioning, respectively. In addition, the task-related pupil dilations also served as the function of cognitive demands during value computation. Results showed that older adults exhibited lower value sensitivity than younger adults; however, increasing information saliency benefitted choice behaviors in both age groups. Furthermore, the decision-aid reduced pupil size during decision-making in both age groups, suggesting decreased cognitive demands of value computation. The beneficial effects from the decision-aid were related to individual’s value sensitivity and the psychophysiological indicators of dopamine and norepinephrine functioning in old age. Lastly, in the third study, a time-vary drift diffusion model that includes starting time parameters was applied to fit the behavioral datasets acquired from the second study. It was aimed to better understand how increasing the saliency of outcome probabilities may affect the dynamics of value-based decision-making. Results showed that older adults started to consider probability, relative to magnitude information, sooner than younger adults, but that their evidence accumulation processes were less sensitive to reward probabilities than that of younger adults. These findings may indicate a noisier and more stochastic information accumulation process during value-based decisions in old age. The decision-aid increased the influence of probability information on the evidence accumulation rate in both age groups but did not alter the relative timing of accumulation for probability versus magnitude in either group. Taken together, the findings in this dissertation not only showed age-related deficits in decision-making and reward learning but also demonstrated that the psychophysiological measures such as spontaneous eye-blink rate, pupillary responses, and locus coeruleus structural integrity may serve as indicators of age and/or individual differences in dopamine and norepinephrine functioning during decision-making and reward-based learning. Moreover, the model-based approach further unraveled age-related alterations in the psychometrics and dynamics of the decision process. The present dissertation may help to identify mechanisms to promote successful aging and the discovery of understanding the role of dopamine and norepinephrine neuromodulation in many fundamental cognitive functions.

A multitude of factors, that either singly, interactively, or sequentially influence the gene-environment interplay in affective and dementia states, include several phases of neurodevelopmental liability in both humans and laboratory animals. Genetic vulnerability for both affective disorders and dementia describes a scenario distinguished by progressive need for concern, particularly in view of the interplay between these areas of ill-health. The contribution of emotional and cognitive expression to personal outcomes, e.g., as a function of affective personality type, a state-dependent analysis of personality characteristics, appears to pervade both the individual's experience of social and physical environments and the performance of cognitive tasks. The role of the endocannabinoids in mental health may offer insights for the psychopharmacology of both cognition and affect. Maladaptive emotional reactions and a defective cognitive ability will contribution to unsatisfactory/maladaptive coping strategies, in turn, leading to further complications of an affective and dysfunctional nature, eventually with a clinical psychopathological outcome. These considerations impinge upon critical issues concerning predisposition and vulnerability. Classical eye-blink conditioning provides a highly established procedure for assessment of defective physiology in models of Alzheimer's dementia. In order to develop a consideration of the array of situations presenting the variation of outcome due to type of affective personality, the role of fear and anxiety and stress in affective states influencing cognition are examined and the critical role of brain circuits mediating emotions influencing cognitive outcomes is discussed.

Syfte: Syftet med den här studien var att undersöka om Spontaneous Eye Blink Rate (SEBR) skiljde sig åt vid läsning på utskrivet papper, surfplatta eller smartphone. Det jämfördes också huruvida fullständiga och ofullständiga blinkningar skiljde sig åt vid läsning på de olika medierna. Metod: Deltagarna (n=29) fick läsa tre olika texter på utskrivet papper, surfplatta och smartphone samtidigt som de filmades. I efterhand granskades samtliga videos två gånger för att räkna fullständiga blinkningar, ofullständiga blinkningar och totalt antal blinkningar (SEBR). Resultat: Den här studien visade att där finns en signifikant skillnad av totalt antal blinkningar vid läsning på utskrivet papper och surfplatta (p=0,03), där blinkningar/minut sjönk med 14,9% vid läsning på utskrivet papper, jämfört med surfplatta. För ofullständiga blinkningar fanns en statistiskt signifikant skillnad mellan utskrivet papper och surfplatta (p=0,02), där antalet ofullständiga blinkningar/minut ökade med 30,0% vid läsning på surfplatta, jämfört med utskrivet papper. Vid läsning på surfplatta och smartphone fanns en signifikant skillnad gällande ofullständiga blinkningar (p=0,01), där antalet ofullständiga blinkningar/minut ökade med 42% vid läsning på surfplattan, jämfört med smartphone.  Slutsats: Spontaneous Eye Blink Rate skiljer sig vid läsning på papper och surfplatta. Ofullständiga blinkningar är flest vid läsning på surfplatta. Inga signifikanta skillnader finns mellan utskrivet papper och smartphone. / Purpose: The purpose of this study was to evaluate whether Spontaneous Eye Blink Rate (SEBR) differ when reading on hard copy, tablet or smartphone. Complete and incomplete blinks were also evaluated to see if there were any differences regarding the hard copy, tablet and smartphone.  Methods: The participants read three different texts on hard copy, tablet and smartphone while they were being filmed. Afterwards, each video was analysed twice in order to count complete blinks, incomplete blinks and total blink rate (SEBR). Results: This study showed that there is a significant difference in total blink rate between reading on hard copy and tablet (p=0.03), where blinks/minute decreased by 14.9% for the hard copy condition. There was also a significant difference in incomplete blinks regarding the two devices (p=0.02), where incomplete blinks increased by 30.0% when reading on tablet. Tablet and smartphone reading also resulted in a significant difference, where incomplete blinks increased  by 42% when reading on tablet (p=0.01). Conclusion: Spontaneous Eye Blink Rate differ when reading on hard copy and tablet. Incomplete blinks increase when reading on tablet. No significant differences are found between hard copy and smartphone.

Une des théories actuellement prépondérante pour expliquer le déclin cognitif observé chez les personnes âgées est une perte généralisée de la fonction inhibitrice. En revanche, de plus en plus d’études révèlent un maintien et même un gain sur le plan émotionnel chez les âgés. Afin de caractériser l’effet de l’âge sur la fonction inhibitrice et sur les émotions, nous avons utilisé le paradigme bien connu du réflexe acoustique de sursaut et de son inhibition par le prépulse, un phénomène reconnu comme reflétant le filtrage sensorimoteur, soit une mesure pré-attentionnelle d’inhibition. Le réflexe acoustique de sursaut est une réponse du corps tout entier à un bruit fort et inattendu et a été mesuré via la magnitude et la latence du clignement des yeux. La présentation d’un son faible (prépulse) quelques millisecondes avant le bruit de sursaut réduit la réponse de sursaut. Deux groupes de participants (jeunes adultes et âgés) ont visionné des images plaisantes, neutres et déplaisantes issues du International Affective Picture System (IAPS), lesquelles étaient associées à des stimuli auditifs évaluant le réflexe acoustique de sursaut et son inhibition par le prépulse. Les résultats démontrent que le réflexe de sursaut est modulé différemment par les émotions chez les jeunes adultes et les âgés. Plus particulièrement, les adultes âgés ont un plus grand réflexe de sursaut que les jeunes adultes lorsqu’ils visionnent des images plaisantes et neutres. Le processus d’inhibition par le prépulse est également modulé différemment par les émotions chez les âgés et les jeunes adultes: les âgés ont une plus grande inhibition du réflexe de sursaut que les jeunes adultes lorsqu’ils visionnent des images plaisantes et déplaisantes, mais ils ne diffèrent pas des jeunes adultes pour les images neutres. Dans l’ensemble, les résultats obtenus ne sont pas compatibles avec une perte d’inhibition chez les adultes âgés, et supportent plutôt un biais émotionnel positif. / Aging is often characterized by a decline in cognitive abilities and a loss of inhibitory function. At the same time there is promising, yet limited to date, evidence of a better emotion regulation with aging. In order to characterize the effect of age on inhibitory function and emotions, in this study the well-known acoustic startle paradigm and its inhibition by a prepulse, a phenomenon known to engage sensorimotor gating, were used. The acoustic startle reflex, a whole-body reflex in response to a loud and unexpected sound, was measured through eye blink magnitude and latency. The inhibition of this acoustic startle response by the presentation of a weak sound, a prepulse, was also measured. Two groups of 30 adults (young and older adults) viewed pleasant, neutral, and unpleasant images from the International Affective Picture System (IAPS) while startle and prepulse trials were presented. The results show that the startle response is differently modulated in the two groups, with the elderly displaying a greater startle reflex while viewing pleasant and neutral pictures compared to young adults. Prepulse inhibition is also differently modulated by emotions in young adults and their older counterparts, with the latter exhibiting a greater inhibition of the startle reflex when viewing pleasant and unpleasant pictures (but not for neutral pictures) compared to young adults. In summary, the present data do not support a decline of the inhibitory function with increasing age, but rather support a positivism effect.

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