a human and a monkey walk into an fMRI scanner…

Tor Wager and I have a “news and views” piece in Nature Methods this week; we discuss a paper by Mantini and colleagues (in the same issue) introducing a new method for identifying functional brain homologies across different species–essentially, identifying brain regions in humans and monkeys that seem to do roughly the same thing even if they’re not located in the same place anatomically. Mantini et al make some fairly strong claims about what their approach tells us about the evolution of the human brain (namely, that some cortical regions have undergone expansion relative to monkeys, while others have adapted substantively new functions). For reasons we articulate in our commentary, I’m personally not so convinced by the substantive conclusions, but I do think the core idea underlying the method is a very clever and potentially useful one:

Their technique, interspecies activity correlation (ISAC), uses functional magnetic resonance imaging (fMRI) to identify brain regions in which humans and monkeys exposed to the same dynamic stimulus—a 30-minute clip from the movie The Good, the Bad and the Ugly—show correlated patterns of activity (Fig. 1). The premise is that homologous regions should have similar patterns of activity across species. For example, a brain region sensitive to a particular configuration of features, including visual motion, hands, faces, object and others, should show a similar time course of activity in both species—even if its anatomical location differs across species and even if the precise features that drive the area’s neurons have not yet been specified.

Mo Costandi has more on the paper in an excellent Guardian piece (and I’m not just saying that because he quoted me a few times). All in all, I think it’s a very exciting method, and it’ll be interesting to see how it’s applied in future studies. I think there’s a fairly broad class of potential applications based loosely around the same idea of searching for correlated patterns. It’s an idea that’s already been used by Uri Hasson (an author on the Mantini et al paper) and others fairly widely in the fMRI literature to identify functional correspondences across different subjects; but you can easily imagine conceptually similar applications in other fields too–e.g., correlating gene expression profiles across species in order to identify structural homologies (actually, one could probably try this out pretty easily using the mouse and human data available in the Allen Brain Atlas).

ResearchBlogging.orgMantini D, Hasson U, Betti V, Perrucci MG, Romani GL, Corbetta M, Orban GA, & Vanduffel W (2012). Interspecies activity correlations reveal functional correspondence between monkey and human brain areas. Nature methods PMID: 22306809

Wager, T., & Yarkoni, T. (2012). Establishing homology between monkey and human brains Nature Methods DOI: 10.1038/nmeth.1869

5 thoughts on “a human and a monkey walk into an fMRI scanner…”

  1. Hmm. I’ll have to check out the paper, but what immediately struck me about this method is that a brain area could be functionally homologous in two species, but not respond to the same stimuli.

    I mean if I see cat food, that doesn’t activate my “Ooh tasty” area. Whereas a nice margharita pizza would do. My cat is the exact opposite – he likes cat food rather than pizza. We could both have an “Ooh tasty” area (the ventral striatum, probably) even though their activity patterns to a given series of stimuli would be quite different.

  2. Yeah, we mentioned that issue in our commentary as well. You could get both false positives (spurious correlations because a single stimulus could drive very different cognitive processes in different species) and false negatives (the problem you mention) fairly easy. It’s not trivial to rule these out as alternative explanations, which is why I’m not so convinced by Mantini et al’s arguments re: the evolution of the human brain. But the method itself is very neat.

  3. How did they manage to publish a paper like this without citing any of the work of Kriegeskorte, which uses quite similar ideas (what he calls “representational dissimilarity matrices”)?

    e.g.,
    Kriegeskorte N (2009). Relating population-code representations between man, monkey, and computational models, Frontiers in Neuroscience doi:10.3389/neuro.01.035.2009.

    Kriegeskorte N, Mur M, Ruff D, Kiani R, Bodurka J, Esteky H, Tanaka K, Bandettini P. (2008). Matching categorical object representations in inferior temporal cortex of man and monkey, Neuron 60(6): 1126-41.

  4. Not sure, Tim. Does seem like a bit of an oversight. We did cite Niko’s work in our commentary, for what it’s worth. I think Mantini et al might argue the stimuli are qualitatively different (i..e, Niko uses well-characterized visual stimuli, and here, the stimulus is dynamic and uncertain, so the methods are different in that sense), but not sure that’s a sufficient explanation.

  5. The value of fMRI research has come under withering criticsm. The SFARI Autism organization was founded by a wealthy philanthropist and fatrer of a daughter diagnosed with autism and funds millions of dollars dedicated to autism research including funding of fMRI research. An article posted on their website states that slight head movement and background noise itself can produce false positives and spurious results.

    The article includes statements by Steve Petersen a nuerosciientist specializing in fMRI research and autism who said ‘“It really, really, really sucks. My favorite result of the last five years is an artifact,” .

    David Fair, a behavioral neuroscientist also stated that ‘It’s going to impact some findings with regard to the robustness, but whether it completely wipes out the findings that are out there is another question”.

    In a tongue in cheek commentary I pointed out the problems of using inter species subjects in fMRI studies.

    You can follow the article and commentary here:

    http://sfari.org/news-and-opinion/news/2012/movement-during-brain-scans-may-lead-to-spurious-patterns

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>