My undergraduate degree was in electronics and communication engineering, which meant sampling theory, reconstruction, and the question of what you are allowed to conclude from an incomplete measurement. At the time I filed that under the dry part of the syllabus.
What I actually cared about was consciousness. I wanted to know how something built out of tissue produces an interior life, and MRI was the first instrument I found that let me look at the thing itself rather than argue about it. So I went toward brain imaging for reasons that were, honestly, more philosophical than technical.
The interest moved. Somewhere between learning how a spin echo works and learning what a Jacobian determinant means, I stopped being fascinated by the mind and started being fascinated by the body carrying it, and by the machinery underneath both. Not only what a method scores, but why it works at all, and what it is quietly assuming while it does.
That is the habit I have not been able to put down. When something works I want to know which part of it is doing the work. When it fails I want to know whether the model was wrong or the measurement was never going to carry the answer. Most of what I have built since is an attempt to make that question answerable instead of arguable.
The field I landed in is medical image computing, and I care about the whole of it rather than one corner. Anatomy and what makes it vary between people. Segmentation, registration, reconstruction, and the geometry and optimisation sitting under all three. How an acquisition decides what a method can possibly recover. What a metric is actually measuring when it agrees with you.
Registration is where that curiosity currently lives, because it states the thing plainly. Every person has a left putamen; no two are the same shape. A smooth invertible map carrying one anatomy onto another has to do exactly the work of that difference, and what the map does is the difference. Atlases, morphometry, longitudinal tracking and label transfer all rest on that one operation. It is quiet infrastructure, and I like that about it.
The sampling theory turned out not to be the dry part. It turned out to be the foundation.