- Canonical Correlates Analysis (CCA) is a multivariate analysis technique for maximizing the correlations between orthagonalized sets of independent and dependent variates
- The codes provided here are for the CCA as performed in Perry et al., (2017, in review), where
- CCA linked rs-fMRI patterns to demographic and cognitive measures in 101 cognitively-normal elders
- And are modified from Smith et al's., (2015) HCP investigation
*Adapted from Perry et al., (2017)
- Normalization and decomposition of functional networks
- CCA
- Basic visualization output
- Parcellation templates used in functional network construction
- MatLab
- PALM
- FSLNETS
- BrainNetViewer (optional for visualisation)
- Functional network matrices of all subjects (i.e. dependent variates in CCA) (connectivity matrices)
- Design Matrix of non-imaging measures (i.e. independent variates in CCA) (DM)
- Motion parameters (i.e. framewise displacement) of functional images (motionFD)
- Centroids of parcellation template employed in functional network construction (COG)
- Within a MatLab terminal run:
[CCAout] = cca_functional(connectivitymatrices, DM, motionFD, COG)
- The resultant data will be stored within the Matlab structure
CCAout
- Which stores important information in the fields of
CCAout
, such as:- grotU: Individual subjects weights for non-imaging measures captured by each CCA mode
- grotV: Individual subjects weights for functional connectivity patterns captured by each CCA mode
- grotR: Correlation between the orthagonalized non-imaging and connectivity patterns
- conload: Loadings of non-imaging measures onto each modes connectivity patterns (i.e. grotV)
- grotstats: Parametric statistical output
- Extracted are the connectivity edges and nodes that are most strongly expressed (i.e. top 250 connections) by the first CCA mode
- For both positive and negative associations with CCA mode
- Users may want to modify their code, depending on their number of significant CCA modes
- Data is extracted in the
.nodes
and.edge
format required for BrainNet Viewer: - For example, for the top positive associations:
- Nodes :
CCA_nodes250topposcons_mode1.nodes
- Edges :
CCA_250topposcons_mode1.edge
- Nodes :
For any questions and more advanced codes/data please contact Alistair Perry (QIMR Berghofer) (alistairgperry at gmail.com)