How to run .nii and .ana files and extract information from the images?

Hi all, I am experiencing some problem in opening .nii and .ana files and extracting information out of them. I need to locate certain regions inside brain and then apply some signal processing algorithms. But the fact is that I am not sure how to work with .nii files. I can open it but I am afraid that I am not using the files properly. In this circumstance, could anyone please help me by instructing how to run and analyze the .nii files in MATLAB?

[Walter Roberson]

These are ANALYZE files?

Are you using the 3rd party toolkit?

http://www.rotman-baycrest.on.ca/~jimmy/NIFTI/