WHAT’S EXACTLY GOING THROUGH YOUR MIND?
NYUAD is helping to pinpoint the neural processes in sign language and linguistics, writes Daniel Bardsley
About 2,300 years ago the Greek philosopher Aristotle argued the purpose of the brain was to help to cool the blood. He thought that consciousness was in our hearts.
Although outlandish, it was perhaps not as ridiculous a suggestion as it appears, given how rich in blood vessels the brain is. But even before Aristotle’s time, many knew that our mental processes take place in the brain and not the heart.
While our knowledge of the brain’s structure and the areas responsible for various functions have moved on immeasurably, our most complex organ has still not yielded all of its secrets to science. So researchers are busy trying to more precisely localise particular functions.
Studies involving New York University Abu Dhabi are helping to provide that for certain neural processes in language.
In a 2015 study published in Brain and Language, Liina Pylkkanen, a professor of linguistics and psychology at New York University and an associate faculty member at NYUAD, led a team who found that, when a person composes basic phrases, a part of the brain called the left anterior temporal lobe was activated in similar ways for many different types of phrases.
There are four main lobes in the brain’s cerebral cortex, which is the part of the brain where higher thought processes take place. The temporal lobe is one. As indicated by its name, it is a frontal section of the left temporal lobe.
In the study, co-authored by NYU researchers Dr Masha Westerlund, Dr Itamar Kastner and Dr Meera Al Kaabi, the same activation pattern – in terms of location and timing – was seen, regardless of whether the person was reading English or Arabic.
But if people are generating language and using sign language to do so, are the brain processes used to generate phrases the same as those used to produce spoken phrases?
A paper has been published in the journal Scientific Reports, in which much of the experimental work was carried out at NYUAD by the lead author, Esti Blanco-Elorrieta.
It was co-written by Prof Pylkkanen, the senior author, along with Dr Kastner and a sign language specialist at San Diego State University, Prof Karen Emmorey.
The study compared results from 11 sign language users in New York and 11 hearing English speakers living in Abu Dhabi, students or faculty members who had recently moved to the UAE. They spoke little or no Arabic.
As in the Arabic-English study, language processing in the brain was measured with magnetoencephalography, which detects the magnetic fields associated with neuronal currents, detailing the measurement of the timing and location of brain activity.
When comparing English speakers and American Sign Language users, the researchers found that activity in the same regions of the brain, and at the same time, was triggered.
“On the one hand it’s a boring replication, but on the other hand it’s amazing because we’re seeing similarity in the face of so much difference. We have to keep in mind the groups are different and we ran these studies in separate countries with different magnetoencephalography machines,” Prof Pylkkanen said.
It demonstrates a deep-rooted similarity in the brain processes when people compose phrases such as “blue cup”, whether these are in sign language or in spoken language.
The researchers had been uncertain, said Prof Emmorey, whether the differences in speaking compared with signing would affect the type of computation in the brain, and the timing at which it happened after a stimulus.
“The hands are much slower but this had no effect on the timing,” Prof Emmorey said. “It’s a very good piece of evidence that we’re dealing with something very fundamental to language.”
Last year, The National reported on a study by Prof Pylkkanen and Blanco-Elorrieta in which only artificial or forced language switching engaged the brain regions called the prefrontal cortex, which is important for inhibition and executive control, and the anterior cingulate cortex, involved in conflict resolution and error monitoring.
When bilingual Arabic and English speakers switched languages freely, there was no activation of such regions.
Blanco-Elorrieta is now looking at neural processes in bilingualism including American sign language and English bilingualism for her PhD.