Contributions in Merlin

Transcranial magnetic stimulation (TMS) produces a direct causal effect on brain activity that can now be studied by new approaches that simultaneously combine TMS with neuroimaging methods, such as functional magnetic resonance imaging (fMRI). In this review we highlight recent concurrent TMS-fMRI studies that illustrate how this novel combined technique may provide unique insights into causal interactions among brain regions in humans. We show how fMRI can detect the spatial topography of local and remote TMS effects and how these may vary with psychological factors such as task-state. Concurrent TMS-fMRI may furthermore reveal how the brain adapts to so-called virtual lesions induced by TMS, and the distributed activity changes that may underlie the behavioural consequences often observed during cortical stimulation with TMS. We argue that combining TMS with neuroimaging techniques allows a further step in understanding the physiological underpinnings of TMS, as well as the neural correlated of TMS-evoked consequences on perception and behaviour. This can provide powerful new insights about causal interactions among brain regions in both health and disease that may ultimately lead to developing more efficient protocols for basic research and therapeutic TMS applications.

Everyday visual scenes contain a vast quantity of information, only a fraction of which can guide our behavior. Properties such as the location, color and orientation of stimuli help us extract relevant information from complex scenes (Treisman and Gelade, 1980; Livingstone and Hubel, 1987). But how does the brain coordinate the selection of such different stimulus characteristics? Neuroimaging studies have revealed significant regions of overlapping activity in frontoparietal cortex during attention to locations and features, suggesting a global component to visual selection (Vandenberghe et al., 2001; Corbetta and Shulman, 2002; Giesbrecht et al., 2003; Slagter et al., 2007). At the same time, the neural consequences of spatial and feature-based attention differ markedly in early visual areas (Treue and Martinez-Trujillo, 2007), implying that selection may rely on more specific top-down processes. Here we probed the balance between specialized and generalized control by interrupting preparatory attention in the human parietal cortex with transcranial magnetic stimulation (TMS). We found that stimulation of the supramarginal gyrus (SMG) impaired spatial attention only, whereas TMS of the anterior intraparietal sulcus (aIPS) disrupted spatial and feature-based attention. The selection of different stimulus characteristics is thus mediated by distinct top-down mechanisms, which can be decoupled by cortical interference.

Reinforcing effects of reward on action are well established, but possible effects on sensory function are less well explored. Here, using functional magnetic resonance imaging, we assessed whether reward can influence somatosensory judgments and modulate activity in human somatosensory cortex. Participants discriminated electrical somatosensory stimuli on an index finger with correct performance rewarded financially at trial end, at one of four different anticipated levels. Higher rewards improved tactile performance and led to increased hemodynamic signals from ventral striatum on rewarded trials. Remarkably, primary somatosensory cortex contralateral to the judged hand was reactivated at the point of reward delivery, despite the absence of concurrent somatosensory input at that time point. This side-specific reactivation of primary somatosensory cortex increased monotonically with level of reward. Moreover, the level of reward received on a particular trial influenced somatosensory performance and neural activity on the subsequent trial, with better discrimination and enhanced hemodynamic response in contralateral primary somatosensory cortex for trials that followed higher rewards. These results indicate that rewards can influence not only classical reward-related regions, but also early somatosensory cortex when a decision is required for that modality.

What decisions should we make? Moral values, rules, and virtues provide standards for morally acceptable decisions, without prescribing how we should reach them. However, moral theories do assume that we are, at least in principle, capable of making the right decisions. Consequently, an empirical investigation of the methods and resources we use for making moral decisions becomes relevant. We consider theoretical parallels of economic decision theory and moral utilitarianism and suggest that moral decision making may tap into mechanisms and processes that have originally evolved for nonmoral decision making. For example, the computation of reward value occurs through the combination of probability and magnitude; similar computation might also be used for determining utilitarian moral value. Both nonmoral and moral decisions may resort to intuitions and heuristics. Learning mechanisms implicated in the assignment of reward value to stimuli, actions, and outcomes may also enable us to determine moral value and assign it to stimuli, actions, and outcomes. In conclusion, we suggest that moral capabilities can employ and benefit from a variety of nonmoral decision-making and learning mechanisms.

Rules on abuse of dominance are used to find a balance between three objectives: 1) ensuring enough competition between firms in order to force them to be efficient and to compete on merit, 2) allowing a certain degree of profitability so that companies have incentives to become more efficient, and 3) achieving an equal distribution of wealth and business opportunities among different sectors of society. While the discussion in developed countries focuses on the first two aspects in order to maximize innovation and growth, developing countries may also want to consider the third dimension and include the reduction of inequality and poverty as objectives of abuse of dominance laws. But even the relationship between the first two aspects tends to vary among regions, because investment depends on factors that differ between developing and developed countries. These factors sometimes contradict each other and it is crucial to find a sound balance between them. Firstly, since developing economies often have smaller markets and, therefore, a lower equilibrium number of firms that can exploit economies of scale and operate efficiently, markets in developing countries are more likely to be concentrated. Furthermore, entry barriers tend to be higher and capital markets are often less developed, which causes obstacles for firms trying to compete with a dominant company. Secondly, large firms play a different role regarding their investment activity in developing countries than they do in more developed economies. Established firms can be important for less developed economies to have a sufficiently high level of investment in production. In such countries, the benefits of increased investments may outweigh efficiency losses that can arise from a more lax treatment of dominant firm conduct. Thirdly, distributional aspects may be especially important for developing countries. Smaller firms, which often represent poorer sectors of society, may have to be given better chances to compete against large dominant companies. Competition law can be used for such public interest issues, but it is crucial that the law gives clear guidance on how these objectives should be balanced against other objectives such as efficiency. The comparison of the EU and the US regarding abuse of dominance shows that significant differences exist even among developed countries. One reason for the disparity is differing assumptions about what types of conduct are harmful and how difficult it is to differentiate them from other conduct. The 'access to market principle' of the EU arises from the assumption that restrictions of market access are harmful to the economy and that a harmful conduct can be distinguished from other, not harmful, conduct. On the other hand, the 'non-intervention principle' of the US is based on the assumption that the distinction of such conduct is difficult, that there is great danger of prohibiting behaviour that is efficient and that the unnecessary prohibition of efficient conduct is severe. One conclusion from the comparison is that these assumptions should be analysed and be grounded on the economic reality. How likely and severe errors of competition authorities are can, for example, be assessed in an analysis of past decisions and their effects on the economy. Support of developing countries' competition authorities in analysing their own cases and the impact of their decisions on the economy would therefore be valuable.

Das Swiss Banking Institute der Universität Zürich präsentiert die Neuauflage der bereits in den Jahren 2000, 2002, 2004 und 2006 durchgeführten Studie "Aktienbesitz in der Schweiz". Die Studie weist den Anteil der direkten und indirekten Aktionäre in der Schweiz nach und zeichnet ein detailliertes Bild des Anlageverhaltens privater Haushalte.