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Mapping the encephalon has come a long way. Far from phrenology and physiognomy, mod medical imaging has enabled things like mapping the connectome of living, good for you human brains and parsing out images from dolphin vocalizations. At present, using voxel-based mapping, a team of UC Berkeley researchers have pinned down the brain regions where we handle certain topics and ideas: a 3D semantic atlas of the brain. Da Vinci would be proud.

Huth et al, 2022, via Nature Video

Subjects in the experiments behind this semantic map had to sit down in an fMRI for hours at a time, listening to The Moth Radio Hour, a storytelling podcast. Later, the researchers would painstakingly match up timestamped fMRI images with timestamped transcripts of the audio stream. This accomplished 2 goals. Commencement, instead of using unmarried words in isolation to study how the encephalon navigates linguistic communication, the study used tongue to create a broader map of semantic concepts. Second, the timestamping permit the team model brain activity every bit a function of what give-and-take was heard, creating a predictive map.

In the team's ain public-facing writeup of their work, they said, "This challenges the current dogma (inherited from studies of language production, as opposed to language comprehension as studied here) holding that language involves merely the left hemisphere." They developed their ain new method of assay, called PrAGMATiC because it is a Probabilistic And Generative Map of Areas Tiling the Cortex, and used information technology to create the master semantic map below.

Huth et al, 2022

At its center, linguistic communication is a system of symbols for carrying information. Nosotros rely on shared understanding of those symbols — phonemes and words — to span the explanatory gap. And human brains are built in shut conformance with a genetically dictated plan, almost of which is mutual to anybody. It seems appropriate, then, that different people might process the same words in similar areas of the brain. Consistent with that idea, lead author Alex Huth said, "The similarity in semantic topography across different subjects is actually surprising." The team found that people process the aforementioned kind of words in the same brain regions — and that virtually a third of the cortex is used for language processing.

Flattened semantic map of the human cerebral cortex. Image: Nature Video

Flattened semantic map of the human cognitive cortex. Related words are colored alike, and responses to related words tend to cluster closely in the brain. Image: Huth et al, via Nature Video

As for how this advances science, medicine or culture — imagine your spouse could wear an actual mood band. Imagine eliminating the spectre of locked-in syndrome, by enabling doctors to compare brain activity to a semantic map and find the person inside. Imagine a existent-time translator that could allow you lot talk with anyone in the earth, no matter what languages y'all both speak.

Personally, I want to see this report repeated simply with a much larger set of subjects, and they should be subjects that come from materially unlike linguistic environments. With what we know about how humans process language on a cognitive level, we could compare semantic mapping between high-context and low-context languages, or cultures that strongly value individuality versus cultures that strongly value belonging. With loftier-fidelity imaging and careful experimental design, neuroscientists could even prod at the divide between linguistic universalism and relativism. (For more on neurolinguistics, read this interesting PDF put forth by some other department at Berkeley.) The authors are eager "to map other aspects of language, such [as] phonemes, syntax then on. […] To explore these bug we therefore plan further studies using unlike stories, different modalities and different languages."

While the paper is currently paywalled at Nature, the authors are quite happy to give access to the total text including supplemental figures. Instructions on how to become it are on their site.