Localizing Language In the Brain

RogerRoast writes "A new study by MIT scientists pinpoints areas of the brain used exclusively for language (PDF), providing a partial answer to a longstanding debate in cognitive science. According to the study, there are parts of our brain dedicated to language and only language. After having their subjects perform the initial language task, which they call a 'functional localizer,' they had each one do a subset of seven other experiments: one on exact arithmetic, two on working memory, three on cognitive control, and one on music; since these are the functions 'most commonly argued to share neural machinery with language.' The authors say the results don't imply that every cognitive function has its own dedicated piece of cortex; after all, we're able to learn new skills, so there must be some parts of the brain that are both high-level and functionally flexible."

Comments

Individual analysis is what is interesting

[dogmatixpsych]

As someone who does neuroimaging research, what appears to be exciting about this approach to fMRI is that it is on an individual-by-individual basis, not at a group level (which is mentioned in the MITNews article). Almost all fMRI work is at a group level. While I perform some group analyses, most of my work is on an individual basis (but I do structural imaging, not functional). Group analyses can have severe limitations that are not always discussed by the researchers and are almost never understood by people outside the field of neuroimaging.

From the article: "It’s the same way for brains. 'Brains are different in their folding patterns, and where exactly the different functional areas fall relative to these patterns,' Fedorenko says. 'The general layout is similar, but there isn’t fine-grained matching.' So, she says, analyzing data by 'aligning brains in some common space is just never going to be quite right. Ideally, then, data would be analyzed for each subject individually; that is, patterns of activity in one brain would only ever be compared to patterns of activity from that same brain."

This process of aligning brains is called registration. Even if you are just working within one subject, there is registration involved (between the functional scan, in this case, and the structural - so you know what part of the brain is being activated). I spend about 25% of my imaging work dealing with checking registrations or trying to improve registrations. It's really a key step in neuroimaging work, one that not enough researchers consider seriously enough. So that's why this approach to fMRI is interesting - the researchers are trying to minimize the effects of poor registration, which can lead to completely invalid results.