Measurement and interpretation of the mismatch negativity

The mismatch negativity (MMN) is a preattentive brain response elicited by changes in repetitive auditory stimulation. Usually, it is identified as the difference between the event-related potential elicited by a high-probabilitystandard and that elicited by a low-probabilitydeviant stimulus. Most likely, MMN is generated by the outcome of a comparison process that registers a difference between the neural representation of the actual input and the memory trace of the standard stimulation. Since its discovery by Näätänen and colleagues in 1978, MMN has become a useful tool for investigating the brain’s auditory information processing in several hundred studies. The present paper describes problems related to the measurement and interpretation of MMN. First, it reviews important features of MMN. Second, it provides technical information about recording and parametrization of this brain wave. Third, it discusses various methodological aspects which may be taken into account in the designing of MMN experiments. Fourth, it addresses some conceptual problems that have to be considered in the proper interpretation of MMN.     

Moral Relativism

Moral relativism comes in many varieties. One is a moral doctrine, according to which we ought to respect other cultures, and allow them to solve moral problems as they see fit. I will say nothing about this kind of moral relativism in the present context. Another kind of moral relativism is semantic moral relativism, according to which, when we pass moral judgements, we make an implicit reference to some system of morality (our own). According to this kind of moral relativism, when I say that a certain action is right, my statement is elliptic. What I am really saying is that, according to the system of morality in my culture, this action is right. I will reject this kind of relativism. According to yet another kind of moral relativism, which we may call epistemic, it is possible that, when one person (belonging to one culture) makes a certain moral judgement, such as that this action is right, and another person (belong to another culture) makes the judgement that the very same action is wrong, they may have just as good reasons for their respective judgements; it is even possible that, were they fully informed about all the facts, equally imaginative, and so forth, they would still hold on to their respective (conflicting) judgements. They are each fully justified in their belief in conflicting judgements. I will comment on this form of moral relativism in passing. Finally, however, there is a kind of moral relativism we could call ontological, according to which, when two persons pass conflicting moral verdicts on a certain action, they may both be right. The explanation is that they make their judgements from the perspective of different, socially constructed, moral universes. So while it is true in the first person's moral universe that a certain action is right, it is true in the second person's moral universe that the very same action is wrong. I explain and defend this version of ontological moral relativism.     

Zur Dynamik der Interaktion in der Supervision

The manifold functions of a supervisor in following the course of complex processes together with the trainee, are: ? to keep the goals of the supervision in view, ? to establish a teaching alliance and to support the wish and ambitions of the candidate to learn, ? to build a platform for the complex interactions with the trainee with regard to the dynamics of the training situation and keeping in mind the institutional influences, ? to lay down the setting for the work, ? to explore and to reflect how transference and counter-transference influence the interaction between patient and analyst as well as between trainee and supervisor, ? to examine these interactions together focussing continuously on the interaction between candidate and patient, and to encourage the candidate to do the same on his own, ? to continuously formulate hypotheses about the core conflict, the transference phenomena and resistance of the patient, ? to explore and reflect on the cooperative work.     

Stimulus-dependent dopamine release in attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is related to an attenuated and dysfunctional dopamine system. Normally, a high extracellular dopamine level yields a tonic dopaminergic input that down-regulates stimuli-evoked phasic dopamine responses through autoreceptors. Abnormally low tonic extracellular dopamine in ADHD up-regulates the autoreceptors so that stimuli-evoked phasic dopamine is boosted. The authors propose that these boosted phasic responses yield hypersensitivity to environmental stimuli in ADHD. Stimuli evoking moderate brain arousal lead to well-functioning performance, whereas either too little or too much stimuli attenuate cognitive performance. Strong, salient stimuli may easily disrupt attention, whereas an environment with impoverished stimuli causes low arousal, which is typically compensated for by hyperactivity. Stochastic resonance is the phenomenon that makes a moderate noise facilitate stimulus discrimination and cognitive performance. Computational modeling shows that more noise is required for stochastic resonance to occur in dopamine-deprived neural systems in ADHD. This prediction is supported by empirical data.