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Biomedical subjects

C van Oss

Publications and source records attributed to C van Oss.

3 recordsLinked to original sources
PubMed1997

Effects of inhibition on neural network development through activity-dependent neurite outgrowth.

Empirical studies have demonstrated that electrical activity of the neuron can directly affect the outgrowth of its neurites. In this paper, the implications of activity-dependent neurite outgrowth are studied in a simple two-cell model, containing one excitatory and one inhibitory cell. We show that activity-dependent outgrowth in combination with the presence of inhibition can account for biostability. The attractors, which can be both point and limit cycle attractors, may be associated with "normal" and "pathological" end states of network development. A slight modification of the model makes it applicable also to a range of other activity-dependent processes in neurons, such as changes in the number of efficacy of receptors. The main results of the previous model are also found in the modified model.

Animals↗
PubMed1996

Spatial pattern formation during aggregation of the slime mould Dictyostelium discoideum.

Stream formation and spiral wave behaviour during the aggregation of Dictyostelium discoideum (Dd) are studied in a model based on the Martiel-Goldbeter equations for cAMP relay, combined with chemotactic motion of Dd cells. The results show that stream formation occurs if the turnover rate of intracellular cAMP is increased. This increase in the turnover rate of cAMP[in] leads to a dependence of the speed of the cAMP wave on the cell density. We propose that this dependence of wave speed on cell density is the underlying mechanism for stream formation. Besides stream formation, increasing the turnover rate of cAMP[in] also results in a spiral wave period that decreases during aggregation, a phenomenon that is commonly observed in situ. Furthermore, the dependence of wave speed on cell density is measured empirically. The speed of the cAMP wave is found to decrease as the wave travels from high to low cell density. This indicates that in situ, wave speed does depend on cell density.

Animals↗