A new paper is about to appear in Neuroimage on the interaction of syntactic complexity and acoustic degradation.
It is written by myself, PhD student Lars Meyer, and Angela Friederici. In a way, the paper brings together one of Angela’s main research questions (which brain circuits mediate the processing of syntax?) with a long-standing interest of mine, that is, how do adverse listening situations affect the comprehension of speech.
The paper is entitled
The paper first establishes that acoustic variants of increasingly complex sentences essentially behave like written versions of these sentences.
The data then neatly show that processing challenging (but legal) syntax under various levels of degradation has a very different effect on the neural circuits involved than profiting from semantics: While the latter has been shown previously to involve more widespread, heteromodal brain areas, the double demand of increasingly complex syntax and an increasingly degraded speech signal (from which the complex syntax has to be parsed) elicit an “upstream” shift of activation back to less abstract processing areas in the superior temporal and prefrontal/frontal cortex.
We tentatively have termed this process “upstream delegation”. We have also tried and established a slightly unusual method to do justice to the fMRI activation data: We have included all z‑scores gathered along certain spatial dimensions, irrespective of whether they were sub- or suprathreshold, and have treated them as distributions. Check it out and let us know what you think.