How can we prove that certain parts of the brain are involved with certain functions? Is it through showing subjects images and then using neuroimaging to see what parts of the brain light up? I am specifically interested in emotions and memory.
The most rudimentary way to know which areas of the human brain are involved with which functions are through animal experiments (what happens if a certain part of the brain is destroyed or, more mercifully, stimulated?) and through observation of stroke or brain cancer patients (patients who lose function in part of their brain due to lack of blood/destruction of part of their brain.) It's easy to tell with a CT scan or an MRI where a brain lesion occurs. Over many, many decades of study (more than a century if you include autopsy results before CT scans were available) the loss of a particular function had been associated with a particular region of the brain. Probably the most famous of the early studies was Paul Broca's discovery in 1861 of where in the brain one aspect of speech/language exists.
With advances in brain surgery (particularly awake craniotomies), it's possible to "fine tune" such study. Add PET and fMRI studies, and you have your answer. Note, though, that not every person's brain is exactly the same.
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