Exposed to the natural light-dark cycle, living beings show robust 24 h rhythms in physiology and behavior. Interestingly, even in the absence of a light-dark cycle, for example in constant... Show moreExposed to the natural light-dark cycle, living beings show robust 24 h rhythms in physiology and behavior. Interestingly, even in the absence of a light-dark cycle, for example in constant conditions, such as under the constant darkness or the constant light, living beings maintain a robust rhythm of which the endogenous period (named free running period, FRP) is close to 24 h. The endogenous rhythms are regulated by a master clock located in the suprachiasmatic nucleus (SCN) of mammals, where the SCN neurons show heterogeneity in the sensitivity to the light. In this article, we examined how this heterogeneity influences the FRP under constant light. Using a Poincare model for the SCN network it is shown that the FRP increases with the increase of the degree of heterogeneity in the sensitivity of neuronal subpopulations to light. Moreover, the presence of a critical value where the periods of the subpopulation diverge, presents a mechanism dictating how some animals remain rhythmic under constant light conditions, while others lose their rhythms completely. Our findings help to understand how the neuronal heterogeneity to light sensitivity in the SCN influences the circadian behavior of the animal. (C) 2022 Elsevier B.V. All rights reserved. Show less
In een cross-sectioneel onderzoek is nagegaan hoe het op de lange duur met CVA patiënten gaat die in het Haaglanden Medisch Centrum te Den Haag opgenomen zijn geweest vanwege een beroerte. Er is... Show moreIn een cross-sectioneel onderzoek is nagegaan hoe het op de lange duur met CVA patiënten gaat die in het Haaglanden Medisch Centrum te Den Haag opgenomen zijn geweest vanwege een beroerte. Er is gekeken naar verschillende aspecten zoals handfunctie, werkhervatting, stemmingsproblemen en zorggebruik. Het blijkt dat, ondanks alle behandelingen die gegeven worden, een grote groep van deze mensen restbeperkingen ervaart. Hun partners voelen zich fors belast, vooral als er sprake is van stemmingsproblemen en als werkhervatting niet lukt. Ook jaren later geeft de meerderheid van CVA patiënten aan nog steeds zorgvragen te hebben die niet beantwoord zijn. Ze lijken beter hun weg te vinden in de eerstelijn voor hun fysieke problemen dan voor hun mentale problemen. Er is gekeken naar de mate waarin eerstelijns behandelaars zich hebben georganiseerd met betrekking tot chronische behandeling en begeleiding van CVA patiënten. Een goed georganiseerd netwerk, met een visie op kwaliteitsaspecten en scholing, is maar op enkele plaatsen in het land beschikbaar. Er zijn aanbevelingen geformuleerd om de ontwikkeling van eerstelijns netwerken voor CVA patiënten te stimuleren. Show less
The human brain is able to flexibly adapt its information processing capacity to meet a variety of cognitive challenges. Recent evidence suggests that this flexibility is reflected in the dynamic... Show moreThe human brain is able to flexibly adapt its information processing capacity to meet a variety of cognitive challenges. Recent evidence suggests that this flexibility is reflected in the dynamic reorganization of the functional connectome. The ascending catecholaminergic arousal systems of the brain are a plausible candidate mechanism for driving alterations in network architecture, enabling efficient deployment of cognitive resources when the environment demands them. We tested this hypothesis by analyzing both resting-state and task-based fMRI data following the administration of atomoxetine, a noradrenaline reuptake inhibitor, compared with placebo, in two separate human fMRI studies. Our results demonstrate that the manipulation of central catecholamine levels leads to a reorganization of the functional connectome in a manner that is sensitive to ongoing cognitive demands. Show less
Fraga Gonzalez, G.; Molen, M.J.W. van der; Zaric, G.; Bonte, M.; Tijms, J.; Blomert, L.; ... ; Van der Molen, M.W. 2016
The suprachiasmatic nucleus (SCN) functions as a circadian clock that drives 24-hour rhythms in physiology and behavior. The SCN neurons function as cell-autonomous oscillators, and the... Show more The suprachiasmatic nucleus (SCN) functions as a circadian clock that drives 24-hour rhythms in physiology and behavior. The SCN neurons function as cell-autonomous oscillators, and the production of a coherent SCN rhythm is dependent upon synchronization among single cells. We investigated how changes in phase-synchronization between individual cells effect the ability of the SCN to phase-shift its rhythm. Empirical and modelling studies revealed larger phase-shifts in synchronized SCN than in desynchronized SCN. The major external stimulus affecting the SCN is light. We explored the ability of melanopsin and rod- and cone photoreceptors to mediate the effects of light on SCN discharge, and found that melanopsin and cones are able to mediate light responses of the SCN. Studies performed in nocturnal species have indicated that the SCN’s rhythmicity is also influenced by the animal’s own behavioral activity. We assessed the effect behavioral activity on the amplitude of the circadian rhythm in SCN electrical discharge rate in the day-active Arvicanthis ansorgei. The results showed acute enhancements of SCN discharge during episodes of behavioral activity. The studies described in this thesis indicate that the SCN is part of a brain network that includes the retina and areas involved in behavioral activity and sleep. Show less
this thesis investigate the impact of land-use changes in conjunction with soil type and seasonal climatic variations on the diversity and dynamics of the soil microbiome in the Pampa ecosystem, a... Show morethis thesis investigate the impact of land-use changes in conjunction with soil type and seasonal climatic variations on the diversity and dynamics of the soil microbiome in the Pampa ecosystem, a subtropical grassland. To access the soil microbiome, a combined approach of sampling strategy, molecular fingerprinting, high-throughput sequencing, the separation of active and dormant populations, and network approach was employed. Land use and soil type are both drivers of bacteria; fungal and archaeal diversity and community structure, and also result in shifts in microbial biomass and metabolic activity. However, the measures of broad-scale functions did not converge with the community structures, evidencing that functioning and structure are not necessarily linked. A large overlap of microbial taxa between land usages were detected indicating the presence of a stable core microbiome resistant to anthropogenic disturbances. The dynamics of microbiome in response to seasonal cl imatic variations showed that moisture was the most important influencing community diversity and structure, with a larger effect on the active, dormant and total community than temperature. The network topology highlighted that each land-use system has a different and specific set of putative key species which might play a role intermediating microbial groups associations. Show less
Popular music in Chinese languages both reflects and influences how its audiences perceive themselves and their position in the world around them. This book analyses the role of popular music in... Show morePopular music in Chinese languages both reflects and influences how its audiences perceive themselves and their position in the world around them. This book analyses the role of popular music in identity formation through detailed comparisons of the pop star Faye Wong, the rock band Second Hand Rose and the electrofolk artist Xiao He, in five thematic chapters. Chapter 1, Place, follows the history of popular music through Shanghai, Hong Kong, Taipei and Beijing, concluding that language is defining. Chapter 2, Genre and Classification, argues that genre distinctions, and by extension class identities, are secondary to affiliations along region, gender, generation and marketability. The psycho-analytical approach of chapter 3, Sex, Gender, and Desire, explores how popular music reiterate and challenge stereotypes surrounding the passive beauty, coolness and brotherhood. Chapter 4, Theatricality, argues that theatrical performances negotiate the boundary between stage world and ordinary reality through make-believe and reflectiveness. Finally, chapter 5, Organizing Music, submits that music happens through reproduction, variation and selection, and in constant interaction with ecologies and collectives. In the end, this book itself strives to make these sounds, images and texts available for the incessant, piecemeal work of worldmaking. Show less
