The interplay between a dietary preference for fat and sugar, gene expression in the dopaminergic system and executive cognition in humans

Obesity is a health issue of both individual and global importance. Evidence from rodent literature suggests that dietary preferences for fat and sugar might influence dopaminergic signaling in the brain and thus executive cognition. These diet-related changes could provide a mechanistic basis potentially explaining obesity-promoting behaviour. However, valid evidence for this link in humans is still scarce. This thesis aimed to add to this gap by studying dopamine-related gene expression profiles in peripheral cells and executive cognition in a human sample (n = 75). The results provide indications for an association between dietary preference and alterations in dopamingeric sigaling on a peripheral gene expression level even though the group differences were not statistically significant. A link to cognition could not be established with the methods applied. Yet, several targets for future research are suggested to further explore this interplay

Lost in Translation? On the Need for Convergence in Animal and Human Studies on the Role of Dopamine in Diet-Induced Obesity

Purpose of Review: Animal and human studies suggest that diet-induced obesity and plasticity in the central dopaminergic system are linked. However, it is unclear whether observed changes depend on diet or obesity, and whether they are specific to brain regions and cognitive functions. Here, we focus on neural and cognitive changes in frontostriatal circuits. Recent Findings: Both diet and obesity affect dopaminergic transmission. However, site and direction of effects are inconsistent across species and studies. Non-specific changes are observed spanning all frontostriatal loops, from sensory input to motivated behaviour. Given the impact of peripheral signals on central dopaminergic signalling and the interaction between the frontostriatal loops, modulation of dopamine likely propagates through all loops and, thus, affects behaviour on various levels of complexity. Summary: To improve convergence between animal and human studies on diet-induced obesity, animal studies should include sophisticated cognitive measures and diets resembling human obesogenic diets, and human studies should adopt diet interventions and longitudinal designs.Peer reviewe

Life within a limited radius: Investigating activity space in women with a history of child abuse using global positioning system tracking

Early experiences of childhood sexual or physical abuse are often associated with functional impairments, reduced well-being and interpersonal problems in adulthood. Prior studies have addressed whether the traumatic experience itself or adult psychopathology is linked to these limitations. To approach this question, individuals with posttraumatic stress disorder (PTSD) and healthy individuals with and without a history of child abuse were investigated. We used global positioning system (GPS) tracking to study temporal and spatial limitations in the participants’ real-life activity space over the course of one week. The sample consisted of 228 female participants: 150 women with PTSD and emotional instability with a history of child abuse, 35 mentally healthy women with a history of child abuse (healthy trauma controls, HTC) and 43 mentally healthy women without any traumatic experiences in their past (healthy controls, HC). Both traumatized groups—i.e. the PTSD and the HTC group—had smaller movement radii than the HC group on the weekends, but neither spent significantly less time away from home than HC. Some differences between PTSD and HC in movement radius seem to be related to correlates of PTSD psychopathology, like depression and physical health. Yet group differences between HTC and HC in movement radius remained even when contextual and individual health variables were included in the model, indicating specific effects of traumatic experiences on activity space. Experiences of child abuse could limit activity space later in life, regardless of whether PTSD develops.Peer Reviewe

Entwicklung und Anwendung miniaturisierter piezoresistiver Dehnungsmesselemente

In der vorliegenden Arbeit werden miniaturisierte piezoresistive Messelemente zur Erfassung der Messgröße Dehnung entwickelt und charakterisiert. Die Anforderungen an die Messelemente werden von den zwei Applikationen miniaturisierte Kraftsensoren für die minimal-invasive Chirurgie sowie Strukturüberwachung adaptronischer Systeme abgeleitet. Anhand einer Literaturrecherche sowie experimentellen Untersuchungen wird der Stand der Technik analysiert. Inhomogen dotierte Siliziumelemente und gedruckte dehnungssensitive Schichten werden ausgewählt und hinsichtlich ihrer Eignung zur strukturintegrierten Dehnungsmessung analysiert. Der Schwerpunkt der Arbeit liegt auf dem Entwurf inhomogen dotierter Siliziumelemente, mit dem Ziel, den Einfluss der Integration auf die Übertragungseigenschaften des Messelements zu quantifizieren. Sowohl die Messelementtopologie als auch die Aufbau- und Verbindungstechnik werden hinsichtlich ihres Einflusses auf die Dehnungsübertragung untersucht. Ein analytisches Modell zur Dehnungsübertragung vom Messobjekt in das Messelement wird für einen uniaxialen Dehnungszustand bestimmt und durch Struktursimulationen sowie experimentelle Untersuchungen bestätigt. Insgesamt werden vier Messelementvarianten präpariert und hinsichtlich ihres statischen Übertragungsverhaltens, der Eigenstörungen sowie des Temperaturverhaltens untersucht. Zur Analyse des Übertragungsverhaltens dient ein im Rahmen der Arbeit entwickelter Vier-Punkt-Biegeversuch, der einen uniaxialen Spannungszustand im Messelement hervorruft. Es kann gezeigt werden, dass durch die Wahl der Aufbau- und Verbindungstechnik sowie durch die Variation der Messelementgeometrie selbst die Empfindlichkeit beeinflusst wird. Sie kann um einen Faktor von bis zu 60 im Vergleich zu herkömmlichen Folien-Dehnungsmesselementen (DMS) gesteigert werden. Die Anwendung der Siliziumelemente erfolgt am Beispiel eines miniaturisierten Kraftsensors für die minimal-invasive Chirurgie. Das Drucken funktionaler Druckfluide mit niedrigen Finishing-Temperaturen wird als zweite Technologie zur Realisierung piezoresistiver Dehnungssensoren analysiert. Der Schwerpunkt dieses Themenkomplexes liegt auf der experimentellen Untersuchung der gedruckten Schichten, um die Eignung der Technologie für die strukturintegrierte Dehnungsmessung bewerten zu können. Zur Realisierung der Schichten werden die Verfahren Sieb- und Inkjetdruck eingesetzt. In Vorversuchen werden die (di-)elektrischen und mechanischen Eigenschaften von vier funktionalen Druckfluiden in Abhängigkeit vom Herstellungsprozess untersucht (Sensorschicht: Silber- bzw. PEDOT:PSS-Suspension, Isolationsschicht: Polyesterlack bzw. Acrylharz). Neben dem spezifischen Widerstand, der Isolationsimpedanz und der Durchschlagfeldstärke sowie der Schichtdicken, die für die Auslegung des Sensors relevant sind, werden auch fertigungstechnische Aspekte berücksichtigt. Im Hinblick auf die Funktionalisierung von Halb¬zeugen für flächige Strukturen wird die Umformbarkeit der gedruckten Schichten untersucht. Zur Ermittlung des zulässigen Umformgrades werden im Zugversuch gedruckte Schichten umgeformt und anhand der elektrischen Größen bewertet. Basierend auf den Ergebnissen der Vor¬versuche werden zwei Sensortopologien entworfen und realisiert. Die statischen Übertragungseigenschaften sowie die Eigenstörungen der gedruckten Sensoren werden experimentell bestimmt und ein Konzept zur strukturintegrierten Dehnungsmessung in einem adaptiven Schwingungstilger umgesetzt. Es zeigt sich, dass die untersuchten Druckfluide im Vergleich zu DMS eine um Faktor zwei reduzierte Empfindlichkeit aufweisen, aufgrund ihrer Überlastfestigkeit und geringen Eigenstörungen jedoch gut für die Dehnungsmessung in Faserverbundwerkstoffen geeignet sind

The interplay between a dietary preference for fat and sugar, gene expression in the dopaminergic system and executive cognition in humans

Obesity is a health issue of both individual and global importance. Evidence from rodent literature suggests that dietary preferences for fat and sugar might influence dopaminergic signaling in the brain and thus executive cognition. These diet-related changes could provide a mechanistic basis potentially explaining obesity-promoting behaviour. However, valid evidence for this link in humans is still scarce. This thesis aimed to add to this gap by studying dopamine-related gene expression profiles in peripheral cells and executive cognition in a human sample (n = 75). The results provide indications for an association between dietary preference and alterations in dopamingeric sigaling on a peripheral gene expression level even though the group differences were not statistically significant. A link to cognition could not be established with the methods applied. Yet, several targets for future research are suggested to further explore this interplay

The interplay between a dietary preference for fat and sugar, gene expression in the dopaminergic system and executive cognition in humans

Obesity is a health issue of both individual and global importance. Evidence from rodent literature suggests that dietary preferences for fat and sugar might influence dopaminergic signaling in the brain and thus executive cognition. These diet-related changes could provide a mechanistic basis potentially explaining obesity-promoting behaviour. However, valid evidence for this link in humans is still scarce. This thesis aimed to add to this gap by studying dopamine-related gene expression profiles in peripheral cells and executive cognition in a human sample (n = 75). The results provide indications for an association between dietary preference and alterations in dopamingeric sigaling on a peripheral gene expression level even though the group differences were not statistically significant. A link to cognition could not be established with the methods applied. Yet, several targets for future research are suggested to further explore this interplay

Neurocognitive capabilities modulate the integration of evidence in schizophrenia

Previous studies have demonstrated a cognitive bias in the integration of disconfirmatory evidence (BADE) in patients with schizophrenia. This bias has been associated with delusions. So far, it is unclear how the integration of evidence is associated with neurocognitive capabilities. In the current study, 31 patients with schizophrenia and 29 healthy controls, matched on age, gender, education and premorbid verbal intelligence, underwent a BADE task. Written scenarios of three consecutive sentences each were presented, which progressively reduced the ambiguity of situations. Participants were asked to rate the plausibility of four possible interpretations and adjust their ratings in response to the provided sentences. Psychometric rating scales and a neuropsychological test battery were applied. Patients displayed a bias in the integration of confirmatory, but not disconfirmatory evidence and a liberal acceptance of belief formation. Correlation analyses revealed no associations of evidence integration with the severity of positive symptoms, but with neurocognitive domains, especially with processing speed, executive functioning, vigilance and working memory. In conclusion, patients with schizophrenia show a bias in evidence integration. Neurocognitive functioning emerged as a modulatory factor that should be considered in further research. Studies investigating BADE in earlier stages of psychosis will be necessary to reveal causal relationship