The skill to talk is certainly one of the important traits that distinguishes people from different animals. Many folks would most likely intuitively equate speech and language. However, cognitive science analysis on sign languages since the Sixties paints a special image: Today it’s clear, sign languages are totally autonomous languages and have a posh group on a number of linguistic ranges similar to grammar and that means. Previous research on the processing of sign language in the human brain had already discovered some similarities and in addition variations between sign languages and spoken languages. Until now, nonetheless, it has been tough to derive a constant image of how each types of language are processed in the brain.
Researchers at the MPI CBS now needed to know which brain areas are literally concerned in the processing of sign language throughout completely different research — and the way massive the overlap is with brain areas that listening to folks use for spoken language processing. In a meta-study lately printed in the journal Human Brain Mapping, they pooled information from sign language processing experiments performed round the world. “A meta-study gives us the opportunity to get an overall picture of the neural basis of sign language. So, for the first time, we were able to statistically and robustly identify the brain regions that were involved in sign language processing across all studies,” explains Emiliano Zaccarella, final writer of the paper and group chief in the Department of Neuropsychology at the MPI CBS.
The researchers discovered that particularly the so-called Broca’s space in the frontal brain of the left hemisphere is certainly one of the areas that was concerned in the processing of sign language in nearly each examine evaluated. This brain area has lengthy been recognized to play a central function in spoken language, the place it’s used for grammar and that means. In order to higher classify their outcomes from the present meta-study, the scientists in contrast their findings with a database containing a number of thousand research with brain scans.
The Leipzig-based researchers have been certainly in a position to affirm that there’s an overlap between spoken and signed language in Broca’s space. They additionally succeeded in exhibiting the function performed by the proper frontal brain — the counterpart to Broca’s space on the left aspect of the brain. This additionally appeared repeatedly in a lot of the sign language research evaluated, as a result of it processes non-linguistic elements similar to spatial or social info of its counterpart. This signifies that actions of the palms, face and physique — of which indicators consist — are in precept perceived equally by deaf and listening to folks. Only in the case of deaf folks, nonetheless, do they moreover activate the language community in the left hemisphere of the brain, together with Broca’s space. They due to this fact understand the gestures as gestures with linguistic content material — as an alternative of as pure motion sequences, as could be the case with listening to folks.
The outcomes show that Broca’s space in the left hemisphere is a central node in the language community of the human brain. Depending on whether or not folks use language in the type of indicators, sounds or writing, it really works along with different networks. Broca’s space thus processes not solely spoken and written language, as has been recognized to date, but additionally summary linguistic info in any type of language typically. “The brain is therefore specialized in language per se, not in speaking,” explains Patrick C. Trettenbrein, first writer of the publication and doctoral pupil at the MPI CBS. In a follow-up examine, the analysis crew now goals to seek out out whether or not the completely different elements of Broca’s space are additionally specialised in both the that means or the grammar of sign language in deaf folks, much like listening to folks.
Materials supplied by Max Planck Institute for Human Cognitive and Brain Sciences. Note: Content could also be edited for fashion and size.