The number of separate domains recognized in the human cortex has doubled, thanks to a newly developed map based on functional MRI brain scans.
Previous studies charted 83 brain regions in each hemisphere of the brain – for example, Broca’s Area, which is thought to be responsible for speech production. The mapping of those regions was typically based on just one measure, such as examining tissue samples under a microscope. The boundaries of the regions were often uncertain.
“The situation is analogous to astronomy, where ground-based telescopes produced relatively blurry images of the sky before the advent of adaptive optics and space telescopes,” study lead author Matthew Glasser, a researcher at Washington University in St. Louis, said in a news release.
To produce a sharper image, Glasser and colleagues at seven research centers conducted fMRI scans on 210 healthy study participants. They looked for similarities and differences in cortical architecture, activity, connectivity and topography – and then fed those readings into software that produced a map of regions with similar qualities.
That map identified 97 additional cortex areas per hemisphere, for a total of 180. The analysis was verified by checking the map against an independent set of readings from 210 other participants.