Results 11 to 20 of about 80,806 (260)

Connectome-based predictive modeling of smoking severity using individualized structural covariance network in smokers

Frontiers in Neuroscience, 2023
IntroductionAbnormal interactions among distributed brain systems are implicated in the mechanisms of nicotine addiction. However, the relationship between the structural covariance network, a measure of brain connectivity, and smoking severity remains ...
Weijian Wang, Yimeng Kang, Xiaoyu Niu, Zanxia Zhang, Shujian Li, Xinyu Gao, Mengzhe Zhang, Jingliang Cheng, Yong Zhang   +8 more
doaj   +1 more source

Percentage amplitude of fluctuation and structural covariance changes of subjective cognitive decline in patients: A multimodal imaging study

Frontiers in Neuroscience, 2022
Back groundSubjective cognitive decline (SCD) may be the first clinical sign of Alzheimer’s disease (AD). The possible neural mechanisms of SCD are not well known.
Ke Xu, Ke Xu, Yichen Wei, Shuming Zhang, Shuming Zhang, Lihua Zhao, Bowen Geng, Bowen Geng, Wei Mai, Pengyu Li, Pengyu Li, Lingyan Liang, Duoli Chen, Duoli Chen, Xiao Zeng, Xiao Zeng, Demao Deng, Peng Liu, Peng Liu   +18 more
doaj   +1 more source

Individual behavioral trajectories shape whole-brain connectivity in mice

eLife, 2023
It is widely assumed that our actions shape our brains and that the resulting connections determine who we are. To test this idea in a reductionist setting, in which genes and environment are controlled, we investigated differences in neuroanatomy and ...
Jadna Bogado Lopes, Anna N Senko, Klaas Bahnsen, Daniel Geisler, Eugene Kim, Michel Bernanos, Diana Cash, Stefan Ehrlich, Anthony C Vernon, Gerd Kempermann   +9 more
doaj   +1 more source

Structural Covariance in the Human Cortex [PDF]

The Journal of Neuroscience, 2005
The morphology of the human cortex varies remarkably across individuals, regardless of overall brain size. It is currently unclear whether related cortical regions covary in gray matter density, as a result of mutually trophic influences or common experience-related plasticity.
Mechelli, A, Friston, K J, Frackowiak, R S, Price, C J   +3 more
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Estimation of a Multiplicative Covariance Structure [PDF]

SSRN Electronic Journal, 2016
We consider a Kronecker product structure for large covariance matrices, which has the feature that the number of free parameters increases logarithmically with the dimensions of the matrix. We propose an estimation method of the free parameters based on the log linear property of this structure, and also a Quasi-Likelihood method.
Hafner, Christian M., Linton, Oliver Bruce, Tang, Haihan   +2 more
openaire   +2 more sources

Age-Related Regional Network Covariance of Magnetic Resonance Imaging Gray Matter in the Rat

Frontiers in Aging Neuroscience, 2020
Healthy human aging has been associated with brain atrophy in prefrontal and selective temporal regions, but reductions in other brain areas have been observed.
Gene E. Alexander, Gene E. Alexander, Gene E. Alexander, Gene E. Alexander, Gene E. Alexander, Gene E. Alexander, Lan Lin, Lan Lin, Lan Lin, Eriko S. Yoshimaru, Pradyumna K. Bharadwaj, Pradyumna K. Bharadwaj, Pradyumna K. Bharadwaj, Kaitlin L. Bergfield, Kaitlin L. Bergfield, Kaitlin L. Bergfield, Lan T. Hoang, Lan T. Hoang, Lan T. Hoang, Monica K. Chawla, Monica K. Chawla, Monica K. Chawla, Kewei Chen, Kewei Chen, James R. Moeller, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Carol A. Barnes, Theodore P. Trouard, Theodore P. Trouard, Theodore P. Trouard   +35 more
doaj   +1 more source

The genetical analysis of covariance structure [PDF]

Heredity, 1977
The analysis of covariance structures (Jöreskog, 1973) is adapted to the simultaneous maximum likelihood estimation of genetical and environmental factor loadings and specific variances. The goodness of fit is tested by chi square and standard errors of parameter estimates can be obtained.
N G, Martin, L J, Eaves
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IDENTIFICATION OF COVARIANCE STRUCTURES [PDF]

Econometric Theory, 2006
Summary: The issue of identification of covariance structures, which arises in a number of different contexts, has been so far linked to conditions on the true parameters to be estimated. In this paper, this limitation is removed. As done by \textit{S. Johansen} [J. Econom. 69, No.
openaire   +1 more source

Shared alterations in hippocampal structural covariance in subjective cognitive decline and migraine

Frontiers in Aging Neuroscience, 2023
IntroductionSubjective cognitive decline (SCD) and migraine are often comorbid. Hippocampal structural abnormalities have been observed in individuals with both SCD and migraine. Given the known structural and functional heterogeneity along the long axis
Chia-Lin Tsai, Kun-Hsien Chou, Kun-Hsien Chou, Pei-Lin Lee, Chih-Sung Liang, Chen-Yuan Kuo, Guan-Yu Lin, Yu-Kai Lin, Yu-Kai Lin, Yi-Chih Hsu, Chien-An Ko, Fu-Chi Yang, Fu-Chi Yang, Ching-Po Lin, Ching-Po Lin, Ching-Po Lin   +15 more
doaj   +1 more source

Testing for instability in covariance structures [PDF]

Bernoulli, 2018
We propose a test for the stability over time of the covariance matrix of multivariate time series. The analysis is extended to the eigensystem to ascertain changes due to instability in the eigenvalues and/or eigenvectors. Using strong Invariance Principles and Law of Large Numbers, we normalise the CUSUM-type statistics to calculate their supremum ...
Kao C, Trapani L, Urga G
openaire   +7 more sources