@article{SommerGarbusowJuengeretal.2017, author = {Sommer, C. and Garbusow, Maria and Juenger, E. and Pooseh, S. and Bernhardt, Nadine and Birkenstock, J. and Schad, Daniel and Jabs, B. and Gloeckler, T. and Huys, Quentin J. M. and Heinz, A. and Smolka, Michael N. and Zimmermann, Ulrich S.}, title = {Strong seduction: impulsivity and the impact of contextual cues on instrumental behavior in alcohol dependence}, series = {Translational Psychiatry}, volume = {7}, journal = {Translational Psychiatry}, publisher = {Nature Publ. Group}, address = {New York}, issn = {2158-3188}, doi = {10.1038/tp.2017.158}, pages = {1209 -- 1222}, year = {2017}, abstract = {Alcohol-related cues acquire incentive salience through Pavlovian conditioning and then can markedly affect instrumental behavior of alcohol-dependent patients to promote relapse. However, it is unclear whether similar effects occur with alcohol-unrelated cues. We tested 116 early-abstinent alcohol-dependent patients and 91 healthy controls who completed a delay discounting task to assess choice impulsivity, and a Pavlovian-to-instrumental transfer (PIT) paradigm employing both alcohol-unrelated and alcohol-related stimuli. To modify instrumental choice behavior, we tiled the background of the computer screen either with conditioned stimuli (CS) previously generated by pairing abstract pictures with pictures indicating monetary gains or losses, or with pictures displaying alcohol or water beverages. CS paired to money gains and losses affected instrumental choices differently. This PIT effect was significantly more pronounced in patients compared to controls, and the group difference was mainly driven by highly impulsive patients. The PIT effect was particularly strong in trials in which the instrumental stimulus required inhibition of instrumental response behavior and the background CS was associated to monetary gains. Under that condition, patients performed inappropriate approach behavior, contrary to their previously formed behavioral intention. Surprisingly, the effect of alcohol and water pictures as background stimuli resembled that of aversive and appetitive CS, respectively. These findings suggest that positively valenced background CS can provoke dysfunctional instrumental approach behavior in impulsive alcohol-dependent patients. Consequently, in real life they might be easily seduced by environmental cues to engage in actions thwarting their long-term goals. Such behaviors may include, but are not limited to, approaching alcohol.}, language = {en} } @article{vanderMeijTemmeLinetal.2018, author = {van der Meij, Marijn W. and Temme, Arnaud J. A. M. and Lin, H. S. and Gerke, Horst H. and Sommer, Michael}, title = {On the role of hydrologic processes in soil and landscape evolution modeling}, series = {Earth science reviews : the international geological journal bridging the gap between research articles and textbooks}, volume = {185}, journal = {Earth science reviews : the international geological journal bridging the gap between research articles and textbooks}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-8252}, doi = {10.1016/j.earscirev.2018.09.001}, pages = {1088 -- 1106}, year = {2018}, abstract = {The ability of water to transport and transform soil materials is one of the main drivers of soil and landscape development. In turn, soil and landscape properties determine how water is distributed in soil landscapes. Understanding the complex dynamics of this co-evolution of soils, landscapes and the hydrological system is fundamental in adapting land management to changes in climate. Soil-Landscape Evolution Models (SLEMs) are used to simulate the development and evolution of soils and landscapes. However, many hydrologic processes, such as preferential flow and subsurface lateral flow, are currently absent in these models. This limits the applicability of SLEMs to improve our understanding of feedbacks in the hydro-pedo-geomorphological system. Implementation of these hydrologic processes in SLEMs faces several complications related to calculation demands, limited methods for linking pedogenic and hydrologic processes, and limited data on quantification of changes in the hydrological system over time. In this contribution, we first briefly review processes and feedbacks in soil-landscape-hydrological systems. Next, we elaborate on the development required to include these processes in SLEMs. We discuss the state-of-the-art knowledge, identify complications, give partial solutions and suggest important future development. The main requirements for incorporating hydrologic processes in SLEMs are: (1) designing a model framework that can deal with varying timescales for different sets of processes, (2) developing and implementing methods for simulating pedogenesis as a function of water flow, (3) improving and implementing knowledge on the evolution and dynamics of soil hydraulic properties over different timescales, and (4) improving the database on temporal changes and dynamics of flow paths.}, language = {en} } @book{OstermeyerKappeMenzeletal.2005, author = {Ostermeyer, Martin and Kappe, Philip and Menzel, Ralf and Sommer, S. and Dausinger, Friedrich}, title = {Laser drilling in thin materials with bursts of ns-pulses generated by stimulated Brillouin scattering (SBS)}, year = {2005}, abstract = {A passively Q-switched laser with a nonlinear mirror on the basis of stimulated Brillouin scattering (SBS), generates bursts of pulses with a few 10 ns pulse duration and a separation between 20-90 mu s. Percussion drilling and trepanning are performed in different materials with 1 mm thickness. The optimum parameter set of these pulse trains with regard to the burr height and ablation rate is investigated. Differences in the processing results between single pulse and multi pulse structures are discussed. In addition the laser allowed for transiently mode locked operation. Results for mode locked and merely Q-switched operation were compared}, language = {en} } @article{SommerKalbeEkstrometal.2014, author = {Sommer, Robert S. and Kalbe, Johannes and Ekstrom, Jonas and Benecke, Norbert and Liljegren, Ronnie}, title = {Range dynamics of the reindeer in Europe during the last 25,000 years}, series = {Journal of biogeography}, volume = {41}, journal = {Journal of biogeography}, number = {2}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0305-0270}, doi = {10.1111/jbi.12193}, pages = {298 -- 306}, year = {2014}, abstract = {Aim To understand the role and significance of the reindeer, Rangifer tarandus (Linnaeus, 1758), as a specific indicator in terms of late Quaternary biogeography and to determine the effects of global climate change on its range and local extinction dynamics at the end of the Ice Age. Location Late Pleistocene/early Holocene range of reindeer over all of central and western Europe, including southern Scandinavia and northern Iberia, but excluding Russia, Belarus and the Ukraine. Methods Radiocarbon-dated subfossil records of R. tarandus from both archaeological and natural deposits younger than 25,000 years were assembled in a database. The distribution area was divided into six representative regions. The C-14 dates were calibrated and plotted chronologically in maps in order to compare presence and absence and regional extinction patterns from one region to another. Main conclusions The late Quaternary record for reindeer in Europe during the last 25 kyr shows a climate-driven dispersal and retreat in response to climate change, with regional variations. The collapse of the mammoth steppe biome did not lead to the local extinction in Europe, as in the case of other megafaunal species. Rangifer tarandus co-existed for about 3000 years during the Late Glacial and early Holocene with typical temperate species such as red deer and roe deer in non-analogue faunal communities. The regional extinction at the end of the Pleistocene coincides with the transition from light open birch/pine forests to pine/deciduous forests.}, language = {en} } @article{KaiserEllerbrockWulfetal.2012, author = {Kaiser, M. and Ellerbrock, Ruth H. and Wulf, M. and Dultz, S. and Hierath, C. and Sommer, M.}, title = {The influence of mineral characteristics on organic matter content, composition, and stability of topsoils under long-term arable and forest land use}, series = {Journal of geophysical research : Biogeosciences}, volume = {117}, journal = {Journal of geophysical research : Biogeosciences}, number = {4}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0148-0227}, doi = {10.1029/2011JG001712}, pages = {16}, year = {2012}, abstract = {In this study, we analyzed the influence of soil mineral characteristics (e. g., clay concentration and mineralogical composition, iron and aluminum oxide concentration and crystallinity, specific surface area, and exchangeable cation concentration) on (i) organic carbon (OC) content (kg m(-2)) and (ii) the concentration (g kg(-1)), composition, and stability of the mineral-associated organic matter (OM) of arable and forest topsoils. We selected seven soil types with different mineral characteristics for this study. For each soil type, samples were taken from topsoils of a deciduous forest and an adjacent arable site. The arable and forest sites have been used continuously for more than 100 years. Na-pyrophosphate soluble OM fractions (OM(PY)), representing mineral-associated OM, were extracted, analyzed for OC and C-14 concentrations, and characterized by FTIR spectroscopy. For the forest and arable topsoils, a linear relationship was found between the OC content and exchangeable Ca. For the arable topsoils (pH 6.7-7.5), correlation analyses indicated that the OCPY concentration increased with an increase in oxalate soluble Fe and Al, exchangeable Ca, and Na-pyrophosphate soluble Mg and Fe concentrations. The stability of OM(PY) determined by the C-14 measurements of the near-neutral arable topsoils was shown to increase with the specific surface area and the concentration of exchangeable Ca. For the acidic forest topsoils (pH < 5), the stability of OM(PY) was found to increase as the pH, and the concentration of C=O groups and Na-pyrophosphate soluble Mg increase.}, language = {en} } @article{ObstSchadHuysetal.2018, author = {Obst, Elisabeth and Schad, Daniel and Huys, Quentin J. M. and Sebold, Miriam and Nebe, Stephan and Sommer, Christian and Smolka, Michael N. and Zimmermann, Ulrich S.}, title = {Drunk decisions}, series = {Journal of Psychopharmacology}, volume = {32}, journal = {Journal of Psychopharmacology}, number = {8}, publisher = {Sage Publ.}, address = {London}, issn = {0269-8811}, doi = {10.1177/0269881118772454}, pages = {855 -- 866}, year = {2018}, abstract = {Background: Studies in humans and animals suggest a shift from goal-directed to habitual decision-making in addiction. We therefore tested whether acute alcohol administration reduces goal-directed and promotes habitual decision-making, and whether these effects are moderated by self-reported drinking problems. Methods: Fifty-three socially drinking males completed the two-step task in a randomised crossover design while receiving an intravenous infusion of ethanol (blood alcohol level=80 mg\%), or placebo. To minimise potential bias by long-standing heavy drinking and subsequent neuropsychological impairment, we tested 18- to 19-year-old adolescents. Results: Alcohol administration consistently reduced habitual, model-free decisions, while its effects on goal-directed, model-based behaviour varied as a function of drinking problems measured with the Alcohol Use Disorders Identification Test. While adolescents with low risk for drinking problems (scoring <8) exhibited an alcohol-induced numerical reduction in goal-directed choices, intermediate-risk drinkers showed a shift away from habitual towards goal-directed decision-making, such that alcohol possibly even improved their performance. Conclusions: We assume that alcohol disrupted basic cognitive functions underlying habitual and goal-directed decisions in low-risk drinkers, thereby enhancing hasty choices. Further, we speculate that intermediate-risk drinkers benefited from alcohol as a negative reinforcer that reduced unpleasant emotional states, possibly displaying a novel risk factor for drinking in adolescence.}, language = {en} } @article{GarbusowSchadSommeretal.2014, author = {Garbusow, Maria and Schad, Daniel and Sommer, Christian and Juenger, Elisabeth and Sebold, Miriam and Friedel, Eva and Wendt, Jean and Kathmann, Norbert and Schlagenhauf, Florian and Zimmermann, Ulrich S. and Heinz, Andreas and Huys, Quentin J. M. and Rapp, Michael A.}, title = {Pavlovian-to-instrumental transfer in alcohol dependence: a pilot study}, series = {Neuropsychobiology : international journal of experimental and clinical research in biological psychiatry, pharmacopsychiatry, Biological Psychology/Pharmacopsychology and Pharmacoelectroencephalography}, volume = {70}, journal = {Neuropsychobiology : international journal of experimental and clinical research in biological psychiatry, pharmacopsychiatry, Biological Psychology/Pharmacopsychology and Pharmacoelectroencephalography}, number = {2}, publisher = {Karger}, address = {Basel}, issn = {0302-282X}, doi = {10.1159/000363507}, pages = {111 -- 121}, year = {2014}, abstract = {Background: Pavlovian processes are thought to play an important role in the development, maintenance and relapse of alcohol dependence, possibly by influencing and usurping ongoing thought and behavior. The influence of pavlovian stimuli on ongoing behavior is paradigmatically measured by pavlovian-to-instrumental transfer (PIT) tasks. These involve multiple stages and are complex. Whether increased PIT is involved in human alcohol dependence is uncertain. We therefore aimed to establish and validate a modified PIT paradigm that would be robust, consistent and tolerated by healthy controls as well as by patients suffering from alcohol dependence, and to explore whether alcohol dependence is associated with enhanced PIT. Methods: Thirty-two recently detoxified alcohol-dependent patients and 32 age- and gender-matched healthy controls performed a PIT task with instrumental go/no-go approach behaviors. The task involved both pavlovian stimuli associated with monetary rewards and losses, and images of drinks. Results: Both patients and healthy controls showed a robust and temporally stable PIT effect. Strengths of PIT effects to drug-related and monetary conditioned stimuli were highly correlated. Patients more frequently showed a PIT effect, and the effect was stronger in response to aversively conditioned CSs (conditioned suppression), but there was no group difference in response to appetitive CSs. Conclusion: The implementation of PIT has favorably robust properties in chronic alcohol-dependent patients and in healthy controls. It shows internal consistency between monetary and drug-related cues. The findings support an association of alcohol dependence with an increased propensity towards PIT.}, language = {en} } @article{SchadGarbusowFriedeletal.2018, author = {Schad, Daniel and Garbusow, Maria and Friedel, Eva and Sommer, Christian and Sebold, Miriam and H{\"a}gele, Claudia and Bernhardt, Nadine and Nebe, Stephan and Kuitunen-Paul, S{\"o}ren and Liu, Shuyan and Eichmann, Uta and Beck, Anne and Wittchen, Hans-Ulrich and Walter, Henrik and Sterzer, Philipp and Zimmermann, Ulrich S. and Smolka, Michael N. and Schlagenhauf, Florian and Huys, Quentin J. M. and Heinz, Andreas and Rapp, Michael A.}, title = {Neural correlates of instrumental responding in the context of alcohol-related cues index disorder severity and relapse risk}, series = {European archives of psychiatry and clinical neuroscience : official organ of the German Society for Biological Psychiatry}, volume = {269}, journal = {European archives of psychiatry and clinical neuroscience : official organ of the German Society for Biological Psychiatry}, number = {3}, publisher = {Springer}, address = {Heidelberg}, issn = {0940-1334}, doi = {10.1007/s00406-017-0860-4}, pages = {295 -- 308}, year = {2018}, abstract = {The influence of Pavlovian conditioned stimuli on ongoing behavior may contribute to explaining how alcohol cues stimulate drug seeking and intake. Using a Pavlovian-instrumental transfer task, we investigated the effects of alcohol-related cues on approach behavior (i.e., instrumental response behavior) and its neural correlates, and related both to the relapse after detoxification in alcohol-dependent patients. Thirty-one recently detoxified alcohol-dependent patients and 24 healthy controls underwent instrumental training, where approach or non-approach towards initially neutral stimuli was reinforced by monetary incentives. Approach behavior was tested during extinction with either alcohol-related or neutral stimuli (as Pavlovian cues) presented in the background during functional magnetic resonance imaging (fMRI). Patients were subsequently followed up for 6 months. We observed that alcohol-related background stimuli inhibited the approach behavior in detoxified alcohol-dependent patients (t = -3.86, p < .001), but not in healthy controls (t = -0.92, p = .36). This behavioral inhibition was associated with neural activation in the nucleus accumbens (NAcc) (t((30)) = 2.06, p < .05). Interestingly, both the effects were only present in subsequent abstainers, but not relapsers and in those with mild but not severe dependence. Our data show that alcohol-related cues can acquire inhibitory behavioral features typical of aversive stimuli despite being accompanied by a stronger NAcc activation, suggesting salience attribution. The fact that these findings are restricted to abstinence and milder illness suggests that they may be potential resilience factors.}, language = {en} } @misc{GarbusowSommerNebeetal.2018, author = {Garbusow, Maria and Sommer, C. and Nebe, S. and Sebold, Miriam and Kuitunen-Paul, S{\"o}ren and Wittchen, H. U. and Smolka, M. and Zimmermann, U. and Rapp, Michael A. and Huys, Q. and Schlagenhauf, Florian and Heinz, A.}, title = {Pavlovian-instrumental transfer in the course of alcohol use disorder}, series = {European psychiatry : the journal of the Association of European Psychiatrists}, volume = {48}, journal = {European psychiatry : the journal of the Association of European Psychiatrists}, publisher = {Elsevier}, address = {ISSY-LES-MOULINEAUX}, issn = {0924-9338}, pages = {S546 -- S546}, year = {2018}, abstract = {Background: Pavlovian processes are thought to play an important role in the development, maintenance and relapse of alcohol dependence, possibly by influencing and usurping on- going thought and behavior. The influence of Pavlovian stimuli on on-going behavior is paradigmatically measured by Pavlovian-to-instrumental-transfer (PIT) tasks. These involve multiple stages and are complex. Whether increased PIT is involved in human alcohol dependence is uncertain. We therefore aimed to establish and validate a modified PIT paradigm that would be robust, consistent, and tolerated by healthy controls as well as by patients suffering from alcohol dependence, and to explore whether alcohol dependence is associated with enhanced Pavlovian-Instrumental transfer. Methods: 32 recently detoxified alcohol-dependent patients and 32 age and gender matched healthy controls performed a PIT task with instrumental go/no-go approach behaviours. The task involved both Pavlovian stimuli associated with monetary rewards and losses, and images of drinks. Results: Both patients and healthy controls showed a robust and temporally stable PIT effect. Strengths of PIT effects to drug-related and monetary conditioned stimuli were highly correlated. Patients more frequently showed a PIT effect and the effect was stronger in response to aversively conditioned CSs (conditioned suppression), but there was no group difference in response to appetitive CSs. Conclusion: The implementation of PIT has favorably robust properties in chronic alcohol- dependent patients and in healthy controls. It shows internal consistency between monetary and drug-related cues. The findings support an association of alcohol dependence with an increased propensity towards PIT.}, language = {en} } @misc{GarbusowSommerNebeetal.2018, author = {Garbusow, Maria and Sommer, Christian and Nebe, Stephan and Sebold, Miriam and Kuitunen-Paul, S{\"o}ren and Wittchen, Hans-Ulrich and Smolka, Michael N. and Zimmermann, Ulrich S. and Rapp, Michael A. and Huys, Quentin J. M. and Schlagenhauf, Florian and Heinz, Andreas}, title = {Multi-level evidence of general pavlovian-to-instrumental transfer in alcohol use disorder}, series = {Alcoholism : clinical and experimental research ; the official journal of the American Medical Society on Alcoholism and the Research Society on Alcoholism}, volume = {42}, journal = {Alcoholism : clinical and experimental research ; the official journal of the American Medical Society on Alcoholism and the Research Society on Alcoholism}, publisher = {Wiley}, address = {Hoboken}, issn = {0145-6008}, pages = {128A -- 128A}, year = {2018}, language = {en} } @article{SeboldNebeGarbusowetal.2017, author = {Sebold, Miriam and Nebe, Stephan and Garbusow, Maria and Guggenmos, Matthias and Schad, Daniel and Beck, Anne and Kuitunen-Paul, S{\"o}ren and Sommer, Christian and Frank, Robin and Neu, Peter and Zimmermann, Ulrich S. and Rapp, Michael A. and Smolka, Michael N. and Huys, Quentin J. M. and Schlagenhauf, Florian and Heinz, Andreas}, title = {When Habits Are Dangerous: Alcohol Expectancies and Habitual Decision Making Predict Relapse in Alcohol Dependence}, series = {Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry}, volume = {82}, journal = {Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry}, publisher = {Elsevier}, address = {New York}, issn = {0006-3223}, doi = {10.1016/j.biopsych.2017.04.019}, pages = {847 -- 856}, year = {2017}, abstract = {BACKGROUND: Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS: Ninety detoxified, medication-free, alcohol-dependent patients and 96 age-and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS: Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS: These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies.}, language = {en} } @article{GarbusowSchadSeboldetal.2016, author = {Garbusow, Maria and Schad, Daniel and Sebold, Miriam and Friedel, Eva and Bernhardt, Nadine and Koch, Stefan P. and Steinacher, Bruno and Kathmann, Norbert and Geurts, Dirk E. M. and Sommer, Christian and Mueller, Dirk K. and Nebe, Stephan and Paul, Soeren and Wittchen, Hans-Ulrich and Zimmermann, Ulrich S. and Walter, Henrik and Smolka, Michael N. and Sterzer, Philipp and Rapp, Michael A. and Huys, Quentin J. M. and Schlagenhauf, Florian and Heinz, Andreas}, title = {Pavlovian-to-instrumental transfer effects in the nucleus accumbens relate to relapse in alcohol dependence}, series = {Addiction biology}, volume = {21}, journal = {Addiction biology}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1355-6215}, doi = {10.1111/adb.12243}, pages = {719 -- 731}, year = {2016}, abstract = {In detoxified alcohol-dependent patients, alcohol-related stimuli can promote relapse. However, to date, the mechanisms by which contextual stimuli promote relapse have not been elucidated in detail. One hypothesis is that such contextual stimuli directly stimulate the motivation to drink via associated brain regions like the ventral striatum and thus promote alcohol seeking, intake and relapse. Pavlovian-to-Instrumental-Transfer (PIT) may be one of those behavioral phenomena contributing to relapse, capturing how Pavlovian conditioned (contextual) cues determine instrumental behavior (e.g. alcohol seeking and intake). We used a PIT paradigm during functional magnetic resonance imaging to examine the effects of classically conditioned Pavlovian stimuli on instrumental choices in n=31 detoxified patients diagnosed with alcohol dependence and n=24 healthy controls matched for age and gender. Patients were followed up over a period of 3 months. We observed that (1) there was a significant behavioral PIT effect for all participants, which was significantly more pronounced in alcohol-dependent patients; (2) PIT was significantly associated with blood oxygen level-dependent (BOLD) signals in the nucleus accumbens (NAcc) in subsequent relapsers only; and (3) PIT-related NAcc activation was associated with, and predictive of, critical outcomes (amount of alcohol intake and relapse during a 3 months follow-up period) in alcohol-dependent patients. These observations show for the first time that PIT-related BOLD signals, as a measure of the influence of Pavlovian cues on instrumental behavior, predict alcohol intake and relapse in alcohol dependence.}, language = {en} }