@phdthesis{Murali2023,
  author    = {Murali, Supriya},
  title     = {Understanding the function of spontaneous blinks by investigating internally and externally directed processes},
  doi       = {10.25972/OPUS-28747},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287473},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Humans spontaneously blink several times a minute. These blinks are strongly modulated during various cognitive task. However, the precise function of blinking and the reason for their modulation has not been fully understood. In the present work, I investigated the function of spontaneous blinks through various perceptual and cognitive tasks. Previous research has revealed that blinks rates decrease during some tasks but increase during others. When trying to understand these seemingly contradictory results, I observed that blink reduction occurs when one engages with an external input. For instance, a decrease has been observed due to the onset of a stimulus, sensory input processing and attention towards sensory input. However, for activities that do not involve such an engagement, e.g. imagination, daydreaming or creativity, the blink rate has been shown to increase. To follow up on the proposed hypothesis, I distinguished tasks that involve the processing of an external stimulus and tasks that involve disengagement. In the first part of the project, I explored blinking during stimulus engagement. If the probability of blinking is low when engaging with the stimulus, then one should find a reduction in blinks specifically during the time period of processing but not during sensory input per se. To this end, in study 1, I tested the influence of task-relevant information duration on blink timing and additionally manipulated the overall sensory input using a visual and an auditory temporal simultaneity judgement task. The results showed that blinks were suppressed longer for longer periods of relevant information or in other words, blinks occurred at the end of relevant information processing for both the visual and the auditory modality. Since relevance is mediated through top-down processes, I argue that the reduction in blinks is a top-down driven suppression. In studies 2 and 3, I again investigated stimulus processing, but in this case, processing was triggered internally and not based on specific changes in the external input. To this end, I used bistable stimuli, in which the actual physical stimulus remains constant but their perception switches between different interpretations. Studies on the involvement of attention in such bistable perceptual changes indicate that the sensory input is reprocessed before the perceptual switch. The results revealed a reduction in eye blink rates before the report of perceptual switches. Importantly, I was able to decipher that the decrease was not caused by the perceptual switch or the behavioral response but likely started before the internal switch. Additionally, periods between a blink and a switch were longer than interblink intervals, indicating that blinks were followed by a period of stable percept. To conclude, the first part of the project revealed that there is a top-down driven blink suppression during the processing of an external stimulus. In the second part of the project, I extended the idea of blinks marking the disengagement from external processing and tested if blinking is associated with better performance during internally directed processes. Specifically, I investigated divergent thinking, an aspect of creativity, and the link between performance and blink rates as well as the effect of motor restriction. While I could show that motor restriction was the main factor influencing divergent thinking, the relationship between eye blink rates and creative output also depended on restriction. Results showed that higher blink rates were associated with better performance during free movement, but only between subjects. In other words, subjects who had overall higher blink rates scored better in the task, but when they were allowed to sit or walk freely. Within a single subject, trial with higher blink rates were not associated with better performance. Therefore, possibly, people who are able to disengage easily, as indicated by an overall high blink rate, perform better in divergent thinking tasks. However, the link between blink rate and internal tasks is not clear at this point. Indeed, a more complex measurement of blink behavior might be necessary to understand the relationship. In the final part of the project, I aimed to further understand the function of blinks through their neural correlates. I extracted the blink-related neural activity in the primary visual cortex (V1) of existing recordings of three rhesus monkeys during different sensory processing states. I analyzed spike related multi-unit responses, frequency dependent power changes, local field potentials and laminar distribution of activity while the animal watched a movie compared to when it was shown a blank screen. The results showed a difference in blink-related neural activity dependent on the processing state. This difference suggests a state dependent function of blinks. Taken altogether, the work presented in this thesis suggests that eye blinks have an important function during cognitive and perceptual processes. Blinks seem to facilitate a disengagement from the external world and are therefore suppressed during intended processing of external stimuli.},
  subject      = {Lidschlag},
  language  = {en}
}
@phdthesis{Ruedenauer2021,
  author    = {R{\"u}denauer, Fabian},
  title     = {Nutrition facts of pollen: nutritional quality and how it affects reception and perception in bees},
  doi       = {10.25972/OPUS-21254},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212548},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2021},
  abstract  = {Nutrients belong to the key elements enabling life and influencing an organism's fitness. The intake of nutrients in the right amounts and ratios can increase fitness; strong deviations from the optimal intake target can decrease fitness. Hence, the ability to assess the nutritional profile of food would benefit animals. To achieve this, they need the according nutrient receptors, the ability to interpret the receptor information via perceptive mechanisms, and the ability to adjust their foraging behavior accordingly. Additionally, eventually existing correlations between the nutrient groups and single nutrient compounds in food could help them to achieve this adjustment. A prominent interaction between food and consumer is the interaction between flowering plants (angiosperms) and animal pollinators. Usually both of the interacting partners benefit from this mutualistic interaction. Plants are pollinated while pollinators get a (most of the times) nutritional reward in form of nectar and/or pollen. As similar interactions between plants and animals seem to have existed even before the emergence of angiosperms, these interactions between insects and angiosperms very likely have co-evolved right from their evolutionary origin. Therefore, insect pollinators with the ability to assess the nutritional profile may have shaped the nutritional profile of plant species depending on them for their reproduction via selection pressure. In Chapter I of this thesis the pollen nutritional profile of many plant species was analyzed in the context of their phylogeny and their dependence on insect pollinators. In addition, correlations between the nutrients were investigated. While the impact of phylogeny on the pollen protein content was little, the mutual outcome of both of the studies included in this chapter is that protein content of pollen is mostly influenced by the plant's dependence on insect pollinators. Several correlations found between nutrients within and between the nutrient groups could additionally help the pollinators to assess the nutrient profile of pollen. An important prerequisite for this assessment would be that the pollinators are able to differentiate between pollen of different plant species. Therefore, in Chapter II it was investigated whether bees have this ability. Specifically, it was investigated whether honeybees are able to differentiate between pollen of two different, but closely related plant species and whether bumblebees prefer one out of three pollen mixes, when they were fed with only one of them as larvae. Honeybees indeed were able to differentiate between the pollen species and bumblebees preferred one of the pollen mixes to the pollen mix they were fed as larvae, possibly due to its nutritional content. Therefore, the basis for pollen nutrient assessment is given in bees. However, there also was a slight preference for the pollen fed as larvae compared to another non-preferred pollen mix, at least hinting at the retention of larval memory in adult bumblebees. Chapter III looks into nutrient perception of bumblebees more in detail. Here it was shown that they are principally able to perceive amino acids and differentiate between them as well as different concentrations of the same amino acid. However, they do not seem to be able to assess the amino acid content in pollen or do not focus on it, but instead seem to focus on fatty acids, for which they could not only perceive concentration differences, but also were able to differentiate between. These findings were supported by feeding experiments in which the bumblebees did not prefer any of the pollen diets containing less or more amino acids but preferred pollen with less fatty acids. In no choice feeding experiments, bumblebees receiving a diet with high fatty acid content accepted undereating other nutrients instead of overeating fat, leading to increased mortality and the inability to reproduce. Hence, the importance of fat in pollen needs to be looked into further. In conclusion, this thesis shows that the co-evolution of flowering plants and pollinating insects could be even more pronounced than thought before. Insects do not only pressure the plants to produce high quality nectar, but also pressure those plants depending on insect pollination to produce high quality pollen. The reason could be the insects' ability to receive and perceive certain nutrients, which enables them to forage selectively leading to a higher reproductive success of plants with a pollinator-suitable nutritional pollen profile.},
  subject      = {Pollen},
  language  = {en}
}
@phdthesis{Gerdes2008,
  author    = {Gerdes, Antje B. M.},
  title     = {Preferential Processing of Phobic Cues : Attention and Perception in Spider Phobic Patients},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-28684},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2008},
  abstract  = {Cognitive views of the psychopathology of anxiety propose that attentional biases toward threatening information play a substantial role in the disorders' etiology and maintenance. For healthy subjects, converging evidence show that threatening stimuli attract attention and lead to enhanced activation in visual processing areas. It is assumed that this preferential processing of threat occurs at a preattentive level and is followed by fast attentional engagement. High-anxious individuals show augmented tendencies to selectively attend toward fear-relevant cues (Mathews, 1990) and exhibit elevated neural processing of threatening cues compared to non-anxious individuals (Dilger et al., 2003). Regarding attentional biases in high-anxious subjects, it remains unanswered up to now whether initial engagement of attention toward threat or difficulties to disengage from threat is an underlying mechanism. Furthermore, little is known whether the preferential (attentive) processing of threatening cues does influence perceptional outcomes of anxious subjects. In order to directly study separate components of attentional bias the first study of this dissertation was a combined reaction time and eye-tracking experiment. Twenty one spider phobic patients and 21 control participants were instructed to search for a neutral target while ignoring task-irrelevant abrupt-onset distractor circles which contained either a small picture of a spider (phobic), a flower (non-phobic, but similar to spiders in shape), a mushroom (non-phobic, and not similar to spiders in shape), or small circles with no picture. As expected, patients' reaction times to targets were longer on trials with spider distractors. However, analyses of eye movements revealed that this was not due to attentional capture by spider distractors; patients more often fixated on all distractors with pictures. Instead, reaction times were delayed by longer fixation durations on spider distractors. This result does not support automatic capture of attention by phobic cues but suggests that phobic patients fail to disengage attention from spiders. To assess whether preferential processing of phobic cues differentially affects visual perception in phobic patients compared to healthy controls, the second study of this dissertation used a binocular rivalry paradigm, where two incompatible pictures were presented to each eye. These pictures cannot be merged to a meaningful percept and temporarily, one picture predominates in conscious perception whereas the other is suppressed. 23 spider phobic patients and 20 non-anxious control participants were shown standardized pictures of spiders or flowers, each paired with a neutral pattern under conditions of binocular rivalry. Their task was to continuously indicate the predominant percept by key presses. Analyses show that spider phobic patients perceived the spider picture more often and longer as dominant compared to non-anxious control participants. Thus, predominance of phobic cues in binocular rivalry provides evidence that preferential processing of fear-relevant cues in the visual system actually leads to superior perception. In combination both studies support the notion that phobic patients process phobic cues preferentially within the visual system resulting in enhanced attention and perception. At early stages of visual processing, this is mainly reflected by delayed attentional disengagement and across time, preferential processing leads to improved perception of threat cues.},
  subject      = {Phobie},
  language  = {en}
}
@phdthesis{Willinger2005,
  author    = {Willinger, Eberhard},
  title     = {Wahrnehmung synthetischer Laute durch Cochlea-Implantat-Patienten},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-23057},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {Die Anzahl der mit einem Cochlea-Implantat versorgten Patienten stieg an der HNO-Universit{\"a}tsklinik W{\"u}rzburg in den letzten Jahren kontinuierlich. Diese Entwicklung wurde wesentlich durch die Einf{\"u}hrung der CIS-Strategie, die den Patienten ein deutlich besseres Sprachverst{\"a}ndnis erm{\"o}glichte, gef{\"o}rdert. Nach wie vor ist es jedoch schwierig und zeitaufw{\"a}ndig, das CI individuell so anzupassen, dass sich daraus f{\"u}r den Patienten ein optimaler Nutzen ergibt. Nicht zuletzt wird die Anpassung eines Cochlea-Implantats dadurch erschwert, dass der deutschen Sprache Ausdrucksmittel fehlen, die es erlauben, H{\"o}reindr{\"u}cke pr{\"a}zise zu beschreiben. Bisher war es bei der Anpassung des MED-EL-Systems {\"u}blich, die Einstellungen des Herstellers f{\"u}r die Bandpassfilter ohne Ver{\"a}nderung zu {\"u}bernehmen. In der vorliegenden Arbeit wird ein Ansatz verfolgt, der eine weitgehend automatische, vom Audiologen unabh{\"a}ngige Anpassung auch der Bandpassfilter an die speziellen Gegebenheiten des Patienten erm{\"o}glichen soll. Dazu wurden f{\"u}nf Cochlea-Implantat-Patienten synthetisch erzeugte Vokale vorgespielt. Die Frequenz der ersten Formanten F1 wurde, ausgehend von der an Normalh{\"o}renden bestimmten Referenzfrequenz, f{\"u}r jeden Vokal gezielt variiert. Die auf diese Weise unterschiedlich synthetisierten Vokale wurden von den Patienten hinsichtlich ihrer "G{\"u}te" in Form von Schulnoten von eins bis sechs bewertet. Gleichzeitig war in dem abgegebenen Urteil auch kodiert worden, welcher Vokal geh{\"o}rt worden war. Aus beiden Informationen wurde eine Punkteskala konstruiert. Auf dieser Skala variieren die Bewertungspunkte von -5 bis +5. Alle Auswertungen basieren auf dieser Skala. Die Abh{\"a}ngigkeit der Bewertungspunkte von der benutzen Synthesefrequenz wurde mit einer Bewertungsfunktion beschrieben, die an die Messwerte angepasst wurde. {\"U}ber das Maximum dieser Funktion wurde auf die optimale Synthesefrequenz f{\"u}r den tieffrequenten Formanten F1 des entsprechenden Vokals geschlossen. Durch Vergleich mit den an den Normalh{\"o}renden gewonnen Referenzfrequenzen konnten Fehlanpassungen erkannt und korrigiert werden. Im Einzelnen wurden aus den Daten folgende Schlussfolgerungen gezogen: a) Die Korrektur der Frequenzzuordnung der Bandp{\"a}sse im Sprachprozessor f{\"u}hrte zu einer besseren Bewertung der Zielvokale bei der Referenzfrequenz. b) Durch die Korrektur verschob sich das Maximum der Bewertungsfunktion wie erwartet in Richtung der Referenzfrequenz. c) Nach der Korrektur zeigte sich ein Trend zu einer besseren Bewertung aller Vokale. d) Die Verteilung der Falschurteile {\"a}nderte sich wie erwartet mit der ge{\"a}nderten Prozessoranpassung. e) In den Daten zeigte sich, dass die Urteile der CI-Patienten und der h{\"o}rgesunden Probanden abh{\"a}ngig vom vorgespielten Vokal in unterschiedlicher Weise mit der Synthesefrequenz variieren. Daraus wurde ein "Empfindlichkeitsmaß" abgeleitet.},
  language  = {de}
}
@phdthesis{Herzlieb2004,
  author    = {Herzlieb, Boris Alexander},
  title     = {Zusammenh{\"a}nge zwischen subjektiver Wahrnehmung und physikalisch messbaren Parametern von D{\"a}mpfungsmechanismen beim Laufvorgang},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-16366},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Die Studie befaßte sich mit der subjektiven Wahrnehmung von Laufschuheigenschaften. 36 L{\"a}ufer wurden {\"u}ber einen Zeitraum von vier Wochen zu zwei Laufschuhtypen und ihrem Lieblingsschuh befragt. Die Laufschuhe unterschieden sich im Leisten und waren ansonsten identisch. Die hierbei gewonnenen Daten wurden dann mit einer parallel angestellten physikalischen Datenerhebung verglichen. Dieser Vergleich konzentrierte sich auf die Teilbereiche aktive D{\"a}mpfung (Pronation etc.), Stabilit{\"a}t, Paßform, Bodenreaktionskr{\"a}fte und Sohlenparameter. Paßform und Stabilit{\"a}t erwiesen sich teilweise als bewußt wahrnehmbar. Geringes Pronationsverhalten und ein flacher Leisten zeigten hier einen positiven Einfluß auf das Stabilit{\"a}tsempfinden. Die Studie zeigte, daß die Probanden nicht in der Lage waren, D{\"a}mpfungsmechanismen, Pronationsverhalten und Bodenreaktionskr{\"a}fte bewußt wahrzunehmen. Allerdings best{\"a}tigen die Ergebnisse die propriozeptive Stimulation eines unbewußten neuromuskul{\"a}ren Regelkreises zur Steuerung neuromuskul{\"a}rer D{\"a}mpfungsmechanismen durch den Fuß, welche die passiven Kraftspitzen beim Fersenaufprall individuell und unabh{\"a}ngig vom verwendeten Schuh konstant halten. Die Unf{\"a}higkeit der Wahrnehmung von D{\"a}mpfungseigenschaften unterstreicht die Notwendigkeit der Gewinnung von individuellen biomechanischen Daten vor Schuhkauf.},
  language  = {de}
}