Monday, May 25, 2015

Newman et al.: "An Event-Related fMRI Study of Syntactic and Semantic Violations" (2001)

This paper reports on a brain imaging study in which people were given either ordinary English sentences or sentences with one of two types of error (p. 349):
  • Yesterday I sailed Todd's hotel to China. (semantic violation)
  • Yesterday I cut Max's with apple. (syntactic violation)
The sentences were presented one word at a time. They don't seem to say when recordings started, but they do mention "critical" words (p. 139).

The results were the following:

The syntactic errors lit up Brodmann's area 6, which includes the premotor cortex. It also activated the a spot in superior temporal gyrus which was either Brodmann's area 21 or 22.

The semantic errors activated a number of regions, including several quite frontal regions. The strongest activation was here inside the the fissure between the two halves of the brain, that is, in the medial section of the cortex.

Here a table:

And here is a picture (Fig. 1, p. 352):

The picture is ugly as hell, but I like that they are so infatuated with this beautiful brain: "The structural image used is from one subject, chosen for its particularly high quality … the choice of one anatomical image over another does not alter the localization of the results—the differences are purely aesthetic." (From the caption of Fig. 1.)

Regarding the syntactic observations, they comment:
Our findings suggest that the superior frontal gyri, including not only premotor cortex, but those portions of it which likely correspond to the supplementary motor area, are involved in the processing of syntactic phrase structure violations. While this is an unusual finding, … it is not unique: Ni et al. (2000, Experiment 2) found superior frontal gyrus activation in response to morphosyntactic violations. (p. 355)
What do we make of this? Well, it would seem that what you do when you read I cut with cake knife is quite literally comparable to pulling an emergency brake: You use the same inhibitory resources as those that are involved in holding yourself back from pushing the wrong button in a stop-go experiment, or training yourself to perform a complex series of movements with your fingers.

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