A new look at physicians' responses to financial incentives: Quality of care, practice characteristics, and motivations.

There is considerable controversy about what causes (in)effectiveness of physician performance pay in improving the quality of care. Using a behavioral experiment with German primary-care physicians, we study the incentive effect of performance pay on service provision and quality of care. To explore whether variations in quality are based on the incentive scheme and the interplay with physicians' real-world profit orientation and patient-regarding motivations, we link administrative data on practice characteristics and survey data on physicians' attitudes with experimental data. We find that, under performance pay, quality increases by about 7pp compared to baseline capitation. While the effect increases with the severity of illness, the bonus level does not significantly affect the quality of care. Data linkage indicates that primary-care physicians in high-profit practices provide a lower quality of care. Physicians' other-regarding motivations and attitudes are significant drivers of high treatment quality.

Who benefits from quality competition in health care? A theory and a laboratory experiment on the relevance of patient characteristics.

We study how competition between physicians affects the provision of medical care. In our theoretical model, physicians are faced with a heterogeneous patient population, in which patients systematically vary with regard to both their responsiveness to the provided quality of care and their state of health. We test the behavioral predictions derived from this model in a controlled laboratory experiment. In line with the model, we observe that competition significantly improves patient benefits as long as patients are able to respond to the quality provided. For those patients, who are not able to choose a physician, competition even decreases the patient benefit compared to a situation without competition. This decrease is in contrast to our theoretical prediction implying no change in benefits for passive patients. Deviations from patient-optimal treatment are highest for passive patients in need of a low quantity of medical services. With repetition, both, the positive effects of competition for active patients as well as the negative effects of competition for passive patients become more pronounced. Our results imply that competition can not only improve but also worsen patient outcome and that patients' responsiveness to quality is decisive.

Rewards for information provision in patient referrals: A theoretical model and an experimental test.

We study whether bonus payments for information provision can improve the information flow between physicians. A primary care physician (PCP) decides on the provision of information of varying qualities to a specialist while referring a patient. Our theoretical model, which includes altruism and loss aversion, predicts that bonus payments increase the provision of both high- and low-quality information. Running a controlled laboratory experiment we find support for this prediction. If the beneficiary of information provision receives a higher payoff than the PCP, we observe that PCPs more often pass on high-quality information when the beneficiary is a patient. If the beneficiary receives a lower payoff than the PCP, the type of the beneficiary (specialist or patient) does not affect the provision of high-quality information.

Sorting into payment schemes and medical treatment: A laboratory experiment.

In this study, we introduce the opportunity for physicians to sort into capitation or fee-for-service payment. Using a controlled medically framed laboratory experiment with a sequential within-subject design allows isolating sorting from incentive effects. We observe a strong preference for fee-for-service payment, which does not depend on subjects' prior experience with one of the two payment schemes. Further, we identify a significant sorting effect. Subjects choosing capitation deviate ex ante less from patient-optimal medical treatment than subjects who sort into fee-for-service payment. Particularly the latter become even less patient-oriented after introducing the choice option. Consequently, the opportunity to choose between fee-for-service and capitation payment worsens patient treatment, if at all. Our results hold for medical and for nonmedical students.

The effects of competition on medical service provision.

We explore how competition between physicians affects medical service provision. Previous research has shown that, without competition, physicians deviate from patient-optimal treatment under payment systems like capitation and fee-for-service. Although competition might reduce these distortions, physicians usually interact with each other repeatedly over time and only a fraction of patients switches providers at all. Both patterns might prevent competition to work in the desired direction. To analyze the behavioral effects of competition, we develop a theoretical benchmark that is then tested in a controlled laboratory experiment. Experimental conditions vary physician payment and patient characteristics. Real patients benefit from provision decisions made in the experiment. Our results reveal that, in line with the theoretical prediction, introducing competition can reduce overprovision and underprovision, respectively. The observed effects depend on patient characteristics and the payment system, though. Tacit collusion is observed and particularly pronounced with fee-for-service payment, but it appears to be less frequent than in related experimental research on price competition.

The dynamics of behavior in modified dictator games.

We investigate the dynamics of individual pro-social behavior over time. The dynamics are tested by running the same experiment with the same subjects at several points in time. To exclude learning and reputation building, we employ non-strategic decision tasks and a sequential prisoners-dilemma as a control treatment. In the first wave, pro-social concerns explain a high share of individual decisions. Pro-social decisions decrease over time, however. In the final wave, most decisions can be accounted for by assuming pure selfishness. Stable behavior in the sense that subjects stick to their decisions over time is observed predominantly for purely selfish subjects. We offer two explanation for our results: diminishing experimenter demand effects and moral self-licensing.

Nuclear envelope localization of LEMD2 is developmentally dynamic and lamin A/C dependent yet insufficient for heterochromatin tethering.

Peripheral heterochromatin in mammalian nuclei is tethered to the nuclear envelope by at least two mechanisms here referred to as the A- and B-tethers. The A-tether includes lamins A/C and additional unknown components presumably INM protein(s) interacting with both lamins A/C and chromatin. The B-tether includes the inner nuclear membrane (INM) protein Lamin B-receptor, which binds B-type lamins and chromatin. Generally, at least one of the tethers is always present in the nuclear envelope of mammalian cells. Deletion of both causes the loss of peripheral heterochromatin and consequently inversion of the entire nuclear architecture, with this occurring naturally in rod photoreceptors of nocturnal mammals. The tethers are differentially utilized during development, regulate gene expression in opposite manners, and play an important role during cell differentiation. Here we aimed to identify the unknown chromatin binding component(s) of the A-tether. We analyzed 10 mouse tissues by immunostaining with antibodies against 7 INM proteins and found that every cell type has specific, although differentially and developmentally regulated, sets of these proteins. In particular, we found that INM protein LEMD2 is concomitantly expressed with A-type lamins in various cell types but is lacking in inverted nuclei of rod cells. Truncation or deletion of Lmna resulted in the downregulation and mislocalization of LEMD2, suggesting that the two proteins interact and pointing at LEMD2 as a potential chromatin binding mediator of the A-tether. Using nuclei of mouse rods as an experimental model lacking peripheral heterochromatin, we expressed a LEMD2 transgene alone or in combination with lamin C in these cells and observed no restoration of peripheral heterochromatin in either case. We conclude that in contrary to the B-tether, the A-tether has a more intricate composition and consists of multiple components that presumably vary, at differing degrees of redundancy, between cell types and differentiation stages.

The Effects of Introducing Mixed Payment Systems for Physicians: Experimental Evidence.

Mixed payment systems have become a prominent alternative to paying physicians through fee-for-service and capitation. While theory shows mixed payment systems to be superior, causal effects on physicians' behavior when introducing mixed systems are not well understood empirically. We systematically analyze the influence of fee-for-service, capitation, and mixed payment systems on physicians' service provision. In a controlled laboratory setting, we implement an exogenous variation of the payment method. Medical and non-medical students in the role of physicians in the lab (N = 213) choose quantities of medical services affecting patients' health outside the lab. Behavioral data reveal significant overprovision of medical services under fee-for-service and significant underprovision under capitation, although less than predicted when assuming profit maximization. Introducing mixed payment systems significantly reduces deviations from patient-optimal treatment. Although medical students tend to be more patient regarding, our results hold for both medical and non-medical students. Responses to incentive systems can be explained by a behavioral model capturing individual altruism. In particular, we find support that altruism plays a role in service provision and can partially mitigate agency problems, but altruism is heterogeneous in the population. Copyright © 2015 John Wiley & Sons, Ltd.

Disruption of fear memory consolidation and reconsolidation by actin filament arrest in the basolateral amygdala.

The dynamic re-arrangement of actin filaments is an essential process in the plasticity of synaptic connections during memory formation. In this study, we determined in mice effects of actin filament arrest in the basolateral complex of the amygdala (BLA) at different time points after memory acquisition and re-activation, using the fungal cytotoxin phalloidin. Our data show a selective disruption of auditory cued but not contextual fear memory, when phalloidin was injected 6h after conditioning. In contrast, no effect was observed when phalloidin was applied after 24h, ruling out an interference with the retrieval or expression of conditioned fear. A comparable result was obtained after memory re-activation, hence suggesting similar actin-dependent mechanisms to be active during consolidation and reconsolidation of auditory fear memory. Biochemical analysis showed that phalloidin-mediated filament arrest leads to a transient increase of highly cross-linked actin filaments in the BLA, evident 2h after injection. Together, these observations indicate that dynamic re-arrangements of actin filaments in the BLA during a late phase of fear memory consolidation and reconsolidation are critical for fear memory storage.

The nuclear organization of Polycomb/Trithorax group response elements in larval tissues of Drosophila melanogaster.

We analysed the nuclear organization of the Polycomb/Trithorax group response element (PRE/TRE) Fab-7 and of other PRE/TREs in larval tissues of D. melanogaster. The results show that pairing/clustering of transgenic and endogenous Fab-7 elements and of other endogenous PRE/TREs occurs only to a limited degree in a highly locus-specific and tissue-specific manner. However, transgenic Fab-7 elements as well as the Fab-7-regulated Abd-B gene and other endogenous loci preferentially occupied defined nuclear regions. Preferred association with the nuclear periphery was observed in the inactive state. However, also in the active state, Fab-7 was often found associated with the nuclear periphery as well as with the boundary of heterochromatin in a fly line- and tissue-specific manner. The boundary between heterochromatin and euchromatin revealed a highly complex architecture in the three-dimensional nuclear space with a close juxtaposition of active and repressed domains. The results suggest that such complex architectures create nuclear microenvironments sustaining specific states of activity of defined PRE/TREs. However, the data also show that the positional behaviour of the transgenic Fab-7 element does not apply to PRE/TREs in general. Altogether, this finding and the highly locus-, tissue-, and fly line-specific behaviour with regard to nuclear positioning and pairing/clustering suggest that the relationships between nuclear organization and functional regulation of PRE/TREs are highly complex and that simple models making general predictions might not be appropriate.

Transcription-dependent spatial arrangements of CFTR and conserved adjacent loci are not conserved in human and murine nuclei.

The human genes CFTR, ASZ1/GASZ, and CTTNBP2/CORTBP2 map to adjacent loci on chromosome 7q31 and display characteristic patterns of nuclear positioning, which strictly correlate with the state of activity. To address the evolutionary conservation of gene positioning, we investigated transcriptional activity and nuclear positioning of the highly conserved murine orthologs and of additional murine genes mapping to the region of conserved synteny on mouse chromosome 6. The results showed that all murine loci investigated constitutively localized in the nuclear interior irrespective of their functional state. Silenced loci did not display preferential association with the nuclear periphery or with chromocenters, respectively, and no differential positioning with respect to the chromosome 6 territory could be observed. This positional behavior of the murine loci was in striking contrast to the positioning of the human orthologs, and the results show that the transcription-dependent positioning of CFTR and adjacent loci has not been conserved. The findings reveal that the nuclear organization of conserved chromosomal regions can change rapidly during evolution and is not always as highly conserved as other features of chromosome organization. Furthermore, the results suggest that the way how nuclear positioning contributes to the regulation of conserved loci can be different in different vertebrate species.

Conserved patterns of nuclear compartmentalization are not observed in the chordate Oikopleura.

BACKGROUND INFORMATION: Recent results from a limited number of eukaryotic model organisms suggest that major principles governing spatial organization of the genome in functionally distinct nuclear compartments are conserved through evolution. RESULTS: We examined the in situ spatial organization of major nuclear components and nuclear patterns of gene loci with strictly defined expression patterns in endocycling cells of the transparent urochordate Oikopleura dioica, a complex metazoan with a very compact genome. Endocycling cells with different functions and similar DNA content displayed distinct topologies of nuclear components. However, the generation of the diverse nuclear architectures did not involve specific local organization of active genes or their preferential amplification. Interestingly, endocycling cells lacked nuclear-envelope-associated heterochromatin and prominent splicing-factor domains, which in mammalian cells associate with transcriptionally silent and active loci respectively. In addition, no correlation was found between transcriptional activity of a locus and its association with chromatin domains rich in specific histone modifications. CONCLUSIONS: Together, these findings and the absence of typical eukaryotic replication patterns reveal a surprisingly limited functional compartmentalization of O. dioica endocycling nuclei. This indicates that robust cell-type-specific gene expression does not necessarily require high levels of spatial genome organization.