Recently, eBioMedicine, a subsidiary of The Lancet, published the latest results of Liu Yong’s team and collaborators at Beijing University of Posts and Telecommunications. Based on multicenter functional magnetic resonance imaging, this study revealed the pattern of changes in whole brain signals in patients with Alzheimer’s disease (AD, commonly known as dementia), and systematically evaluated the relationship between whole brain signal changes and cognitive changes, brain functional network integration changes and disease biological pathways.
Patients with Alzheimer’s disease have significant cognitive decline, which is strongly related to abnormal characterization of brain functional activity and brain functional networks. Therefore, exploring the abnormal brain network change pattern in Alzheimer’s disease patients is one of the important means to reveal the mechanism of cognitive impairment of the disease.
Generally, whole-brain signaling (GS) refers to the average signal in the whole brain or gray matter region in fMRI images, and many studies use this signal as a possible nuisance signal and remove it from fMRI image preprocessing.
“It is worth noting that in recent years there have been studies that have shown that whole-brain signaling is closely associated with arousal, psychiatric illness, and behavior.” Liu Yong told China Science News, “The study of whole-brain signals in Alzheimer’s disease patients can help us better perform preprocessing of functional magnetic resonance images.” It also promotes the understanding of brain functional network abnormalities in Alzheimer’s disease. ”
The researchers used data from the Multicenter Alzheimer’s Disease Database (MCADI) established by many hospitals in China and the Alzheimer’s Disease Neuroimaging Program (ADNI) in the United States to study a total of 131 cases. The signal energy of GS time series was calculated, and it was found that there was no significant change in the energy of the whole brain signal time series in patients with Alzheimer’s disease. After that, they used the correlation between local brain activity time series and whole brain signal time series (GSCORR) as an indicator of the distribution of whole brain signals in the whole brain, and found that the spatial distribution of whole brain signals has a similar pattern in normal people and patients, and all show high levels in the posterior cingulation, anterior cunei, and subparietal lobules.
Distribution of GS and GSCORR among normal people and patients Photo courtesy of respondents
Using a linear model, the team revealed changes in the distribution of whole-brain signals in Alzheimer’s disease patients and explored their correlation with cognitive ability.
“Patients with Alzheimer’s disease have elevated GSCORR in the prefrontal lobe and reduced GSCORR in the temporal lobe, cingulate gyrus, hippocampus, etc.” Pindong Chen, the first author of the paper and a doctoral student at the Institute of Automation of the Chinese Academy of Sciences, said, “We also found that GSCORR at these sites was significantly correlated with patients’ cognitive ability, and this result was independently verified in the ADNI dataset.” ”
In further research, the team constructed a brain network based on the brain network group map, using the clustering coefficient and shortest path length to represent the topological attributes of network integration and separation of brain functional networks, respectively. The results showed that the changes of the whole brain signal distribution in Alzheimer’s disease patients were strongly correlated with the coupling changes of the brain functional network, which further revealed the relationship between the change of the whole brain signal distribution and the abnormal change of the brain functional network, suggesting that the whole brain signal may be one of the potential factors of abnormal change of the functional network of Alzheimer’s disease.
“This study reveals the relationship between whole-brain signal changes and brain network changes in Alzheimer’s disease patients, clarifies the importance of whole-brain signaling for disease research, and provides new ideas for the study of brain functional networks in Alzheimer’s disease patients.” Liu Yong said. (Source: Zhang Shuanghu, China Science News)
Related paper information:https://doi.org/10.1016/j.ebiom.2023.104455