Identifying diurnal variability of brain connectivity patterns using graph theory

Significant differences exist in human brain functions affected by time of day and by people’s diurnal preferences (chronotypes) that are rarely considered in brain studies. In the current study, using network neuroscience and resting-state functional MRI (rs-fMRI) data, we examined the effect of both time of day and the individual’s chronotype on whole-brain network organization. In this regard, 62 participants (39 women; mean age: 23.97 ± 3.26 years; half morning- versus half evening-type) were scanned about 1 and 10 h after wake-up time for morning and evening sessions, respectively. We found evidence for a time-of-day effect on connectivity profiles but not for the effect of chronotype. Compared with the morning session, we found relatively higher small-worldness (an index that represents more efficient network organization) in the evening session, which suggests the dominance of sleep inertia over the circadian and homeostatic processes in the first hours after waking. Furthermore, local graph measures were changed, predominantly across the left hemisphere, in areas such as the precentral gyrus, putamen, inferior frontal gyrus (orbital part), inferior temporal gyrus, as well as the bilateral cerebellum. These findings show the variability of the functional neural network architecture during the day and improve our understanding of the role of time of day in resting-state functional networks

Player's functioning in the communities of Internet based and augmented reality MMO games

Celem obecnych badań była analiza funkcjonowania graczy w społeczności internetowej gry MMO oraz gry wykorzystującej rozszerzoną rzeczywistość. Badanie podzielono na dwa etapy. Pierwszy etap miał charakter eksploracyjny, obejmował studium przypadku krakowskiej społeczności graczy Ingress. Przeprowadzono wywiad fokusowy, analizę kanałów chatu oraz wykorzystano wnioski z obserwacji uczestniczącej. Na podstawie uzyskanych wyników zdefiniowano tło teoretyczne dla drugiego etapu badań. W drugim etapie badań porównywano poziom posiadanego przez graczy kapitału społecznego oraz ich zaangażowanie w życie społeczności. Dane zebrane zostały od graczy obu rodzajów gier. Do mierzenia kapitału społecznego wykorzystano zmodyfikowaną Internetową Skalę Kapitału Społecznego Williamsa (2006), a do mierzenia zaangażowania w życie społeczności kwestionariusz własnego autorstwa. Wbrew przewidywaniom opartym na dotychczasowej literaturze przedmiotu nie zaobserwowano istotnych różnic pomiędzy grupami w zakresie integracyjnego kapitału społecznego. Zaangażowanie w życie społeczności również nie różniło się istotnie w dwóch badanych grupach. Wśród graczy Ingress zaobserwowano natomiast istotnie wyższy poziom łączącego kapitału społecznego. Uzyskane wyniki pozwalają przypuszczać, że społeczności tworzone w obrębie badanych gier pod wieloma względami są do siebie podobne, pomimo różnicy realności przestrzeni w której funkcjonują. Sugeruje się, że dla nawiązywania bliskich relacji interpersonalnych kluczowe mogą być inne zmienne niż samo występowanie kontaktu twarzą w twarz. Wskazuje się również na konieczność dalszych badań.In the present study social functioning of members from two groups of MMO games communities was analized. The study was divided in two parts. In the first part case study of Ingress players was conducted. Data was gathered via focus interveiw, chat analyssis and participation obserwation. Conclusions of this study were used to establish theoretical framework for the second part. In the second part of the study data about Ingress and World of Warcraft player’s social capital and engagement in the game community was gathered. Modified William’s (2006) Internet Social Capital Scales were used. To assess engagement new scale was constructed. In contrary to predictions based on previous research, analysis showed no significant differences in player’s bonding social capital. Bridging social capital was significantly higher for Ingress players and engagement in the community showed no differences. The results indicate strong similarities between both communities, despite one lacking direct personal interaction between players

Brain functional network architecture reorganization and alterations of positive and negative affect, experiencing pleasure and daytime sleepiness in cataract patients after intraocular lenses implantation

Background: Cataracts are associated with progressive blindness, and despite the decline in prevalence in recent years, it remains a major global health problem. Cataract extraction is reported to influence not only perception, attention and memory but also daytime sleepiness, ability to experience pleasure and positive and negative affect. However, when it comes to the latter, the magnitude and prevalence of this effect still remains uncertain. The current study aims to evaluate the hemodynamic basis of daytime sleepiness, ability to experience pleasure and positive and negative affect in cataract patients after the intraocular lens (IOL) implantation. Methods: Thirty-four cataract patients underwent resting-state functional magnetic resonance imaging evaluation before and after cataract extraction and intraocular lens implantation. Both global and local graph metrics were calculated in order to investigate the hemodynamic basis of excessive sleepiness (ESS), experiencing pleasure (SHAPS) as well as positive and negative affect (PANAS) in cataract patients. Results: Eigenvector centrality and clustering coefficient alterations associated with cataract extraction are significantly correlated with excessive sleepiness, experiencing pleasure as well as positive and negative affect. Conclusions: The current study reveals the hemodynamic basis of sleepiness, pleasure and affect in patients after cataract extraction and intraocular lens implantation. The aforementioned mechanism constitutes a proof for changes in functional network activity associated with postoperative vision improvement

Neuroimaging of chronotype, sleep quality and daytime sleepiness : structural T1-weighted magnetic resonance brain imaging data from 136 young adults

The dataset contains structural T1-weighted magnetic resonance brain imaging data from 136 young individuals (87 females; age range from 18 to 35 years old) along with questionnaire-assessed measurements of trait-like chronotype, sleep quality and daytime sleepiness. The recruitment criteria excluded individuals with self-reported history of psychiatric or neurological conditions and current medication use. All the brain imaging sessions were performed between 5:20 PM and 8:55 PM in order to control the effect of time of day on acquired images. The data is mostly useful to scientists interested in circadian rhythmicity. It can be deployed in large-scale multicenter meta-analyzes investigating the structural brain correlates of chronotypes in humans. Additionally, the data could be of use in investigations into the effects of sleeping habits and latitude on brain anatomy

Brain under fatigue - can perceived fatigability in multiple sclerosis be seen on the level of functional brain network architecture?

Background: Fatigue is one of the most common symptoms of multiple sclerosis (MS), significantly affecting the functioning of the patients. However, the neural underpinnings of physical and mental fatigue in MS are still vague. The aim of our study was to investigate the functional architecture of resting-state networks associated with fatigue in patients with MS. Methods: The sum of 107 high-functioning patients underwent a resting-state scanning session and filled out the 9-item Fatigue Severity Scale (FSS). Based on the FSS score, we identified patients with different levels of fatigue using the cluster analysis. The low-fatigue group consisted of n = 53 subjects, while the high-fatigue group n = 48. The neuroimaging data were analyzed in terms of functional connectivity (FC) between various resting-state networks as well as amplitude of low-frequency fluctuation (ALFF) and fractional amplitude of low-frequency fluctuations (fALFF). Results: Two-sample t-test revealed between-group differences in FC of posterior salience network (SN). No differences occurred in default mode network (DMN) and sensorimotor network (SMN). Moreover, differences in fALFF were shown in the right middle frontal gyrus and right superior frontal gyrus, however, no ALFF differences took place. Conclusion: Current study revealed significant functional network (FN) architecture between-group differences associated with fatigue. Present results suggest the higher level of fatigue is related to deficits in awareness as well as higher interoceptive awareness and nociception