The generation of phase differences and frequency changes in a network model of inferior olive subthreshold oscillations

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedicationIt is commonly accepted that the Inferior Olive (IO) provides a timing signal to the cerebellum. Stable subthreshold oscillations in the IO can facilitate accurate timing by phase-locking spikes to the peaks of the oscillation. Several theoretical models accounting for the synchronized subthreshold oscillations have been proposed, however, two experimental observations remain an enigma. The first is the observation of frequent alterations in the frequency of the oscillations. The second is the observation of constant phase differences between simultaneously recorded neurons. In order to account for these two observations we constructed a canonical network model based on anatomical and physiological data from the IO. The constructed network is characterized by clustering of neurons with similar conductance densities, and by electrical coupling between neurons. Neurons inside a cluster are densely connected with weak strengths, while neurons belonging to different clusters are sparsely connected with stronger connections. We found that this type of network can robustly display stable subthreshold oscillations. The overall frequency of the network changes with the strength of the inter-cluster connections, and phase differences occur between neurons of different clusters. Moreover, the phase differences provide a mechanistic explanation for the experimentally observed propagating waves of activity in the IO. We conclude that the architecture of the network of electrically coupled neurons in combination with modulation of the inter-cluster coupling strengths can account for the experimentally observed frequency changes and the phase differences.Peer reviewedFinal Published versio

Obrada industrijskih i komunalnih otpadnih voda u slijednom šaržnom reaktoru

A mixture of Industrial wastewater from chemical industry (varnish, paint and pigments production) and municipal wastewater was treated in pilot sequencing batch reactor (SBR). Results of the pilot experiments show that the foaming problem has great influence on the behavior of SBR, especially when the ratio between industrial and municipal wastewater is very high. Foaming problem was negligible when the mixture with φ; 20 % of the industrial wastewater and j = 80 % of the municipal wastewater was treated. With the operational cycle of 6 h with anoxic (non-aerated) and aerobic (aerated) phase the required effluent quality was obtained according to regulations for treated wastewater that flows into the recipient. Operational cycle (aerobic phase) can be 60 min shorter at minimal organic and nitrogen loading.Smjesa industrijskih otpadnih vodâ (proizvodnja lakova, boja i pigmenata) i komunalnih otpadnih voda obrađivana je u pilotnom slijednom šaržnom reaktoru (SBR). Rezultati eksperimenata pokazuju da pjenjenje znaeajno utjeee na rad SBR-a, posebice u uvjetima velikih omjera industrijskih i komunalnih otpadnih voda na ulazu u reaktor. Problem pjenjenja je beznaeajan kada se obrađuje mješavina j = 20 % industrijskih otpadnih voda i j = 80 % komunalnih otpadnih voda. S operacijskim ciklusom od 6 sati s anoksienom (faza bez aeriranja) i aerobnom (aeriranom) fazom postiže se željena kvaliteta efluenta za obrađenu otpadnu vodu koja odlazi u recipijent. Operacijski ciklus (aerobna faza) može biti i 60 min kraća ako je sadržaj organskih tvari i dušika pri punjenju reaktora minimalan