Amplification of local changes along the timescale processing hierarchy

Small changes in word choice can lead to dramatically different
interpretations of narratives. How does the brain accumulate and integrate
such local changes to construct unique neural representations for
different stories? In this study we created two distinct narratives by
changing only a few words in each sentence (e.g. “he” to “she” or
“sobbing” to “laughing”) while preserving the grammatical structure across
stories. We then measured changes in neural responses between the two
stories. We found that the differences in neural responses between the two
stories gradually increased along the hierarchy of processing timescales.
For areas with short integration windows, such as early auditory cortex,
the differences in neural responses between the two stories were
relatively small. In contrast, in areas with the longest integration
windows at the top of the hierarchy, such as the precuneus, temporal
parietal junction, and medial frontal cortices, there were large
differences in neural responses between stories. Furthermore, this gradual
increase in neural difference between the stories was highly correlated
with an area’s ability to integrate information over time. Amplification
of neural differences did not occur when changes in words did not alter
the interpretation of the story (e.g. “sobbing” to “crying”). Our results
demonstrate how subtle differences in words are gradually accumulated and
amplified along the cortical hierarchy as the brain constructs a narrative
over time. This dataset contains of 18 subjects passively listening to an
audio Story1 (“MilkyWay”) and 18 subjects passively listening to an audio
Story2 (“Vodka”). Each subject has one functional run of 297 TRs, during
which s/he heard an audio story (“Milky Way” or “Vodka”), while viewing a
gray screen. Subjects were instructed to attend to the details of the
narrative. Download the README.txt file for a detailed description of this
dataset's content