Hi Hugh,
The tabularText type is intended for reading tabular data from text files, which doesn't match the structure of .mat files containing 4D arrays. For .mat files, you should consider using a fileDatastore. Here is an example to show how you can achieve this:
fds = fileDatastore('filename',"ReadFcn",@load,"FileExtensions",".mat");
data1 = read(fds);
For more information on fileDatastore function, refer to the following MathWorks documentation:
