External Email - Use Caution
Hello Freesurfer experts,
I am trying to perform a GLM, using the volume of a brain region as a covariate. I am doing a two-group, one covariate design. I originally tried to use QDEC to facilitate the process and received an error message that the mri_glmfit command had failed. I then saw that QDEC was deprecated and followed the instructions set out on the freesurfer wiki for doing it manually (https://secure-web.cisco.com/1W0gEAYXZeH6XMYzikihrf4Ct-vcV_3e-WmTr1eqTVlVGWz...).
I received the same error message as I had with QDEC on the command line:
ERROR: MatrixResidualForming(): X is not invertable RD is not invertable n = 1
This only occurs for certain of the brain regions used as covariates; for others, the QDEC and command-line streams work perfectly. Additionally, I've noticed that if I input different numbers for the covariate values in the fsgd file, the command runs smoothly.
I haven't been able to find a similar error on the mailing list, does anyone have an idea of how to work around this? I would greatly appreciate it.
Please find attached my fsgd file, and the full log of what happens after I run the mri_glmfit command (when it works and when it doesn't) The hands.fsgd file doesn't work, whereas the hands_works.fsgd file does.
Freesurfer version: 7.2.0, Ubuntu 20.04, Windows WSL
Best wishes, Alex
--
Alexandre Piot, MSc. Queen Square Institute of Neurology President of the Application of Psychedelics Society https://secure-web.cisco.com/1txv4iCOx4-mObxXkQBwlHnKAPMdNbmkUOMySvRIxTq9ls1uXZ8Kl62y3I49HdkLsX6y7u-cbb0hhFAgyYtQiLyvLqmJHRpVile95hsJIW_BkEPsZYU7xlCSImzrBqWQ04vGC-z5o197phurtwnpjWg9swrt2VVrxiiXYGg9bY0RbMOrknb9AaoPwF5FSDuMc0WVXrwnhjXQY6v4i38hVb6sLx6MLR2rCdDLI8W_lEtTFtoddcERVMfMlp1QPST7zgdW1ISSG1NIw0Y7AGPrRMAOgyDEDDbcO5Bw5ZAdy0JZpVjRnYzg9UIT_Svi--kUWS1MEmI_sDO3lstJ-3GIgMQ/https%3A%2F%2Fwww.uclsap.com%2F -- UCL UNITy Projecthttps://secure-web.cisco.com/11-VCBFrldtskQk64mTlGciM29YjbhiPBFq0qJNEn4t16fq2dpqPk8MULNrPk_hdW3xFgDWoez2dpX7V5EsWwjhjv5xLowcqQlWm8H8z1bfrLct3k0RqTnpX1n8ctYdYTBN4YZweUcivxmxcuvMem-Gc6V7-VqRYMBpF6H6kHTK_UcUi5UnP5yWRqhIkMLWkdPffFie-WcMxkLkdKIpTISAHztKFwrtv1Z0KJlrr03qryskIQu6LNxCa5spVh0LxIs6qkUPD7pRD2E8dl-jERSFNiw0WJygtI9HdMjxfWc8x9C2KVtbdX5UmF1A-hcqoRaqNXrfS42WsaQI_sTTEKdA/https%3A%2F%2Fwww.psychedelicunit.com%2F