AI layperson here. Is there something like an MRI scan for a neural network? Imagining I could take a foundation model, run it on my specialized task, and meas

AI layperson here. Is there something like an MRI scan for a neural network? Imagining I could take a foundation model, run it on my specialized task, and measure which regions of the neural network light up. Then I could carve out unused regions of the network to create a more lightweight model. Or is this a silly idea?