Background: Local network connectivity disruptions in Alzheimer's disease patients have been found using graph analysis in BOLD fMRI. Other studies using MEG and cortical thickness measures,... Show moreBackground: Local network connectivity disruptions in Alzheimer's disease patients have been found using graph analysis in BOLD fMRI. Other studies using MEG and cortical thickness measures, however, show more global long distance connectivity changes, both in functional and structural imaging data. The form and role of functional connectivity changes thus remains ambiguous. The current study shows more conclusive data on connectivity changes in early AD using graph analysis on resting-state condition fMRI data. Methodology/Principal Findings: 18 mild AD patients and 21 healthy age-matched control subjects without memory complaints were investigated in resting-state condition with MRI at 1.5 Tesla. Functional coupling between brain regions was calculated on the basis of pair-wise synchronizations between regional time-series. Local (cluster coefficient) and global (path length) network measures were quantitatively defined. Compared to controls, the characteristic path length of AD functional networks is closer to the theoretical values of random networks, while no significant differences were found in cluster coefficient. The whole-brain average synchronization does not differ between Alzheimer and healthy control groups. Post-hoc analysis of the regional synchronization reveals increased AD synchronization involving the frontal cortices and generalized decreases located at the parietal and occipital regions. This effectively translates in a global reduction of functional long-distance links between frontal and caudal brain regions. Conclusions/Significance: We present evidence of AD-induced changes in global brain functional connectivity specifically affecting long-distance connectivity. This finding is highly relevant for it supports the anterior-posterior disconnection theory and its role in AD. Our results can be interpreted as reflecting the randomization of the brain functional networks in AD, further suggesting a loss of global information integration in disease. Show less
Unfairness increases noise annoyance. Noise annoyance increases due to unfair sound management. Fair sound management reduces annoyance, however only when the sound pressure level is high,... Show moreUnfairness increases noise annoyance. Noise annoyance increases due to unfair sound management. Fair sound management reduces annoyance, however only when the sound pressure level is high, concludes Eveline Maris based on two laboratory experiments.Being exposed to man-made sound is more than mere exposure: it is a social experience, too: You expose Me. This social hypothesis of noise annoyance has been confirmed in two laboratory experiments. Participants were exposed to aircraft noise (sound pressure level (SPL): 50 or 70 dB A) and treated either in a neutral, fair, or unfair manner. The results show that besides SPL, also the fairness of the procedure determines the level of noise annoyance. The first experiment shows an interaction effect of procedural fairness and SPL: annoyance ratings are significantly lower in the fair than in the neutral condition, but the effect is found only when SPL is 70 dB. The second experiment shows a main effect of procedural unfairness on noise annoyance: annoyance ratings are significantly higher in the unfair than in the neutral conditions, regardless of SPL.The findings imply that, in addition to noise reduction engineering, application of knowledge on the social side of noise annoyance can help reduce future noise annoyance levels. Show less
