Serotonin at the level of the amygdala and orbitofrontal cortex modulates distinct aspects of positive emotion in primates.

Impaired top-down regulation of the amygdala, and its modulation by serotonin (5-HT), is strongly implicated in the dysregulation of negative emotion that characterizes a number of affective disorders. However, the contribution of these mechanisms to the regulation of positive emotion is not well understood. This study investigated the role of 5-HT within the amygdala and the orbitofrontal cortex (OFC), on the expression of appetitive Pavlovian conditioned emotional responses and their reversal in a primate, the common marmoset. Its effects were compared to those of the amygdala itself. Having developed conditioned autonomic and behavioural responses to an appetitive cue prior to surgery, marmosets with excitotoxic amygdala lesions failed to display such conditioned autonomic arousal at retention, but still displayed intact cue-directed conditioned behaviours. In contrast, 5,7-DHT infusions into the amygdala, reducing extracellular 5-HT levels, selectively enhanced the expression of appetitive conditioned behaviour at retention. Similar infusions into the OFC, producing marked reductions in post-mortem 5-HT tissue levels, had no overall effect on autonomic or behavioural responses, either at retention or during reversal learning, but caused an uncoupling of these responses, thereby fractionating emotional output. These data demonstrate the critical role of the amygdala in the expression of appetitive autonomic conditioning, and the region-selective contribution of 5-HT in the amygdala and OFC, respectively, to the expression of conditioned behaviour and the overall coordination of the emotional response. They provide insight into the neurochemical mechanisms underlying the regulation of positive emotional responses, advancing our understanding of the neural basis of pathologically dysregulated emotion

Serotonergic, brain volume and attentional correlates of trait anxiety in primates.

Trait anxiety is a risk factor for the development and maintenance of affective disorders, and insights into the underlying brain mechanisms are vital for improving treatment and prevention strategies. Translational studies in non-human primates, where targeted neurochemical and genetic manipulations can be made, are critical in view of their close neuroanatomical similarity to humans in brain regions implicated in trait anxiety. Thus, we characterised the serotonergic and regional brain volume correlates of trait-like anxiety in the marmoset monkey. Low- and high-anxious animals were identified by behavioral responses to a human intruder (HI) that are known to be sensitive to anxiolytic drug treatment. Extracellular serotonin levels within the amygdala were measured with in vivo microdialysis, at baseline and in response to challenge with the selective serotonin reuptake inhibitor, citalopram. Regional brain volume was assessed by structural magnetic resonance imaging. Anxious individuals showed persistent, long-term fearful responses to both a HI and a model snake, alongside sustained attention (vigilance) to novel cues in a context associated with unpredictable threat. Neurally, high-anxious marmosets showed reduced amygdala serotonin levels, and smaller volumes in a closely connected prefrontal region, the dorsal anterior cingulate cortex. These findings highlight behavioral and neural similarities between trait-like anxiety in marmosets and humans, and set the stage for further investigation of the processes contributing to vulnerability and resilience to affective disorders.This research was supported by a Medical Research Programme Grant (G0901884) from the Medical Research Council UK (MRC) to Angela Roberts, and a PhD studentship from MRC and final-term funding from Trinity College, Cambridge, UK to Yevheniia Mikheenko.This is the author accepted manuscript. The final version is available from NPG at http://www.nature.com/npp/journal/v40/n6/full/npp2014324a.htm

Efficient Computer Simulations of the Structure and the Dynamics of beta- Cyclodextrins and Water in Cristalline Structures

Titelblatt und Inhaltsverzeichnis 1 Einleitung 2 Grundlagen 2.1 Cyclodextrine 2.2 Wasserstoffbrücken 2.3 Unordnung 2.4 Molekulardynamik 2.5 Diffusion 3 Effizienzvergleich 3.1 Verletliste 3.2 Zellenliste 3.3 Vergleich 4 Durchführung der Simulation 4.1 MD-Simulationen der großen Systeme 4.2 MD-Simulationen der kleinen Systeme 4.3 MD-Simulation eines beta-Cyclodextrinmoleküls in Wasser 5 Überblick über die Ergebnisse 5.1 rms-Fluktuationen 5.2 Torsionswinkel 5.3 Bindungswinkel zwischen den Glucoseringen 5.4 O(4)´ - O(4) Abstände 5.5 Mittlere Molekülstrukturen 5.6 Wasserstoffbrückenbindungen 5.7 Diffusion 6 Zusammenfassung und Ausblick Anhang A: Abkürzungen Anhang B: Parameter Anhang C: Tabellen Anhang D: Kugeloberflächeneinteilung LiteraturverzeichnisDie Computersimulationen zur Molekulardynamik(MD) von beta-Cyclodextrinen und Wasser im Kristallverbund sind durch Vergleich der root mean square Fluktuationen der Atomkoordinaten der beta-Cyclodextrinein der MD mit den isotropen Verrückungsparametern der Kristallstrukturen aus der Arbeitsgruppe Saenger überprüft. Die Aufteilung der Unordnung auf kristalline und molekulare, die im Gegensatz zum Experiment in den Auswertungen der MD- Simulationen möglich ist, zeigt etwa gleichgroße Anteile bei den Ringatomen und höhere molekulare Unordnung für die peripheren. Die Auswirkung erhöhter Flexibilität der peripheren Atome auf die Verteilungsdichten einiger Torsionswinkel und weiterer Strukturparameter der beta-Cyclodextrine ergibt Abweichungen, deren Ursache in der mangelhaften Eignung der CHARMM- Energiefunktion für die Zucker liegen dürfte. Insgesamt ergeben sich im Vergleich mit den experimentellen Daten qualitativ gute Übereinstimmungen der Simulationsergebnisse für den Molekülaufbau und seine Dynamik. Es werden Muster und Lebensdauer von Wasserstoff(H-)brücken im Kristall untersucht, die die Struktur der beta-Cyclodextrinmoleküle und des Kristalls stabilisieren. Für H-brückenbindungen, deren Struktur und Dynamik können die MD-Simulationsergebnisse mit den experimentellen Daten qualitativ, teilweise auch quantitativ verglichen werden mit deutlichen Abhängigkeiten von der Feuchte des Kristalls. Bei der MD mit geringer Feuchte sind nicht mehr ausreichend viele Wassermoleküle zur Stabilisierung vorhanden und bei hoher Feuchte konkurrieren die Wassermoleküle untereinander und können daher keine stabilen größeren H-brückensysteme bilden. Wichtigster Punkt der Auswertung ist die Dynamik der Wassermoleküle im beta- Cyclodextrinkristall mit Bestimmung der Diffusionskonstanten des Wassers im Kristall und der Diffusionsrichtung mittels eines neu entwickelten schnellen Algorithmus. So kann ein geschlossener Diffusionsweg durch den Kristall bestimmt werden, der durch die beta-Cyclodextrinringstruktur verläuft und eine Verbindung der Wassermoleküle in den Cyclodextrinringen mit denen außerhalb zuläßt. Das neu entwickelte Simulationsprogramm bietet mit der Verwendung von Zellenlisten im Vergleich zu der Verletliste in CHARMM partiell Rechenzeitvorteile.I verified the computer simulations of the structure and the dynamics of beta- cyclodextrins and water in crystalline structures with a comparison of the root mean square fluctuations of the molecular dynamics (md) simulations and the crystal structure experimentally solved at different humidities by Dr Steiner 1994 in the group of Prof Dr Saenger, which results in good agreement for the atoms in the glucose rings. The outer atoms have a larger flexibility in the simulations than in the experiment. I investigated the different types of disorder in the molecular and in the crystalline part. This shows that the crystalline part looks like the molecular part of disorder for the atoms of the glucose rings. The molecular part of the disorder is larger than the crystalline part of the disorder for the outer atoms. This additional characterisation of disorder is possible on simulations, but difficult in experiments. The effects of the flexibility on the distribution of some torsion angles and other structural parameters of the beta-cyclodextrins were investigated too. Some deviations from the experiment with respect to sugars became evident. These differences are due to a weakness in the quality of the energy function in CHARMM. All of my comparisons indicate, that there is a good principal agreement between the measurement and the simulation data describing the structure and dynamics of the crystals of the beta- cyclodextrins. The pattern and the lifetimes of hydrogen bonds in the crystal were calculated. The hydrogen bonds stabilize the structure of the crystal and the beta-cyclodextrin molecules. I get results for the structure and dynamics of the hydrogen bonds from the md simulations. These results correlate with the experimental results qualitatively in many aspects and quantitatively in some aspects. There is an obvious dependency on the humidity of the crystal. There are not enough water molecules in the crystal to stabilize the structure at low humidity. At high humidity the water molecules compete with one another, so they do not form larger systems of hydrogen bonds. The most important point of the evaluation of the md simulations is the dynamics of the water molecules in the crystal. I determine the diffusion constant and path of water in the crystal. To do this, I have developed a fast algorithm to derive the most probable drift direction. It was possible to find a diffusion path through the crystal, which goes through the beta-cyclodextrin rings. The inner and outer water molecules are connected by this diffusion path. The newly developed simulation program has advantages in CPU time compared to CHARMM. This is due to the usage of a list of cells instead of the Verlet list

Workbench for the computer simulation of underwater gated viewing systems

In this paper we introduce a software tool for image based computer simulation of an underwater gated viewing system. This development is helpful as a tool for the discussion of a possible engagement of a gated viewing camera for underwater imagery. We show the modular structure of implemented input parameter sets for camera, laser and environment description and application examples of the software tool. The whole simulation includes the scene illumination through a laser pulse with its energy pulse form and length as well as the propagation of the light through the open water taking into account complex optical properties of the environment. The scene is modeled as a geometric shape with diverse reflective areas and optical surface properties submerged in the open water. The software is based on a camera model including image degradation due to diffraction, lens transmission, detector efficiency and image enhancement by digital signal processing. We will show simulation results on some example configurations. Finally we will discuss the limits of our method and give an outlook to future development

Simulation of the interaction of a high energy laser beam with the sea surface in the short wavelength infrared

The knowledge of the interaction of a high energy laser beam with a dynamic sea surface is of great practical interest in maritime environments. The components transmitted into the sea and reflected at the sea surface have to be considered. The calculation of energy transfer into the sea is fundamental to the prediction of upper-ocean heating and temperature-dependent optical properties of the sea, which in turn influence its reflectance characteristics. In addition, the spatial energy (or power) distribution of the laser beam reflected at the dynamic sea surface is also of high significance. For the estimation of the laser light energy reflected into a specific spatial direction, several parameters need to be considered, e.g., wind speed, wind direction, and fetch. The calculated amount of light energy reflected into a specific direction varies statistically and depends largely on the dynamics of the wavy sea surface. A 3D simulation of a dynamic sea surface is presented interacting with a high energy laser beam in the short wavelength infrared spectral band. The simulation computes the upper-ocean heating, the temperature-dependent Fresnel reflectances, and the absorption in seawater considering the laser geometric configuration. For the reflectance calculations, a bistatic configuration of the laser source and receiver is regarded, where the receiver positions are on a virtual hemisphere having the laser spot center as the center point. The specular reflection of the laser beam at the sea surface is modeled by an analytical statistical bidirectional reflectance distribution function of the sea surface. The simulation is restricted to sea surfaces heated to the boiling point to avoid complex phase transition effects between water and gas. For a high energy laser beam focused on a small laser spot on the evolving wavy sea surface, the maximum expected reflected laser power is calculated for the specular forward- and back-reflection direction for glints. The probability of occurrence and temporal occurrence of those glint events is estimated for both directions

5th Data Science Symposium, GEOMAR

Modern digital scientific workflows - often implying Big Data challenges - require data infrastructures and innovative data science methods across disciplines and technologies. Diverse activities within and outside HGF deal with these challenges, on all levels. The series of Data Science Symposia fosters knowledge exchange and collaboration in the Earth and Environment research community. We invited contributions to the overarching topics of data management, data science and data infrastructures. The series of Data Science Symposia is a joint initiative by the three Helmholtz Centers HZG, AWI and GEOMAR Organization: Hela Mehrtens and Daniela Henkel (GEOMAR