Modeling and analyzing higher-order correlations in non-Poissonian spike trains.

Measuring pairwise and higher-order spike correlations is crucial for studying their potential impact on neuronal information processing. In order to avoid misinterpretation of results, the tools used for data analysis need to be carefully calibrated with respect to their sensitivity and robustness. This, in turn, requires surrogate data with statistical properties common to experimental spike trains.

Ambiguous figures and binding: EEG frequency modulations during multistable perception.

Ambiguous figures induce sudden transitions between rivaling percepts. We investigated electroencephalogram frequency modulations of accompanying change-related de- and rebinding processes. Presenting the stimuli discontinously, we synchronized perceptual reversals with stimulus onset, which served as a time reference for averaging.

Discontinuous presentation of ambiguous figures: how interstimulus-interval durations affect reversal dynamics and ERPs.

If we observe an ambiguous figure, our percept is unstable and alternates between the possible interpretations. Periodically interrupting the presentation sizably modulates the spontaneous reversal rate. We here studied event-related potential (ERP) correlates of the neural processes underlying these strong modulations.

The dual klepsydra model of internal time representation and time reproduction.

We present a model of the internal representation and reproduction of temporal durations, the 'dual klepsydra' model (DKM). Unlike most contemporary models operating on a 'pacemaker-counter' scheme, the DKM does not assume an oscillatory process as the internal time-base. It is based on irreversible, dissipative processes in inflow/outflow systems (leaky klepsydrae), whose states are continuously compared; if their states are equal, durations are subjectively perceived as equal.

[To the behaviour of cadmium and lead in children with a different cadmium or lead burden].

An epidemiological study of 413 randomly chosen children in age of 2--14 years living in an industrial town is presented. According to their place of residence they were either burdened with cadmium from a forge or with lead from the traffic. The different burden was refelcted not only in the blood lead level but also in blood cadmium level respectively.

[The relationships between blood lead, erythrocyte count, blood hemoglobin concentration and age in children (author's transl)].

With increasing age of the children and increasing hemoglobin, hematocrit and serum protein levels, the lead concentrations of the blood in the children dropped. By contrast, high lead concentrations in blood correlate with low MCV and high erythrocyte values. The possible causes are discussed.