This is Research on Brain month on Researchista and this is our guest of the week, I would normally say, but this is not just an usual introduction. This is such a genuinely nice person and friend, I wish to transmit at least a little bit from the inspiration and huge support that Joao has been giving to research communication. I would like to thank him for accepting to break the ice on Research and BRAIN month – with its related topics that are included in one field, called ‘Neuroscience’. It start with how brain helps us express clearly and use language to solve our problems and grow. Welcome to our Special Guest Dr. Joao Correia, originally from Portugal, Experienced Researcher at Maastricht University.
LANGUAGE: YOUR KEY TO THE WORLD.
We all have the impression that the brain is vast, and that vastness allows us to perform a long list of human functions. One of the unique functions that humans have is by far the ability to communicate. Human communication is direct and self-motivated. We do not only express ourselves to others, but we do it with the intention to change the behavior and knowledge of others.
My research dives into the unknown neural circuits of the communicating brains via speech and language. I try to understand how we speak and how we understand the speech of others, and in addition how these seemingly natural capacities serve the memory and thoughts and above all, shape the advanced societies of our world. Imagine, a car crash test.
A car at high speed drives against a brick wall. This is – figuratively – what happens in the tympanic membrane of our ears when you hear something. Sound waves (travelling at 340 meters per second) bring auditory information into our ears, which transforms this mechanical energy into electric signals that can be interpreted by our brains.
Without this basic physical and neural capacity to receive sound information, for example from speech, infants wouldn’t develop normal speech and linguistic capabilities. Our ability to speak or to read owes much to this initial training of speech sound perception, such as our parents voice.
As the auditory cortices in the left and right hemispheres, receive signals from spoken language, they start to link to others brain areas that are being coherently stimulated. For example, we hear different melodic tunnes (also called ‘signatures’ or ‘prosodies’) when our parents want to provide us a positive or negative feedback for education. Or we hear the word ‘water’ coherently together with the experience of drinking water. In sum, our senses start becoming linked, originating richer memory representations (auditory, visual, tactile, olfactory or emotional). How exactly these links are created and used in everyday life remains largely unknown.
Another linguistic faculty that is poorly understood is how we speak. Remember how swimming is a super exercise because it uses so many muscles of our body? Well, speaking uses more than 100 muscles, from the diaphragm and costal muscles – to create air flow – to multiple muscles of the larynx – to create the necessary pressure – to transform air flow onto sound waves – and finally – muscles of the vocal tract like the lips and tongue – to shape those sound waves onto concrete speech sounds. Due to our highly linked brain, we are capable to develop speaking abilities purely from hearing other people speaking, as well as, experiencing our own attempts to speak.
This link between auditory and motoric brain systems is often referred to as sensorimotor integration, because it provides a platform to integrate sensory and motor components. Sensorimotor integration is a key aspect of speech development, everyday speaking and comprehension. In a nutshell, we speak in a certain way because of how we hear and we hear in a certain way because of how we speak.
I am deeply in love with the versatility and complexity of sensorimotor integration, as it has the potential to explain multiple mysteries of the communicating brains, how comprehension and speaking develop normally and abnormally or how the brain learns to read.
Until recently, to ask these questions would necessarily lead to difficult philosophic and psychological discussions for which my engineering background wouldn’t be ready. However, in addition to these critical points in science, today we can image the human brain safely and with unprecedented detail, which allows directly to test and create hypothesis for how humans communicate…
Functional MRI (magnetic resonance imaging) allows taking magnetic pictures of the brain as people execute scientific experiments, including speaking or listening to speech. The pictures,
reflect oxygen consumption within each small 3D pixel (or voxel) and are extremely rich in detail. However, such a complex capability is not present in one or two voxels, but distributed among the vast neural circuitry of the brain. Thousands of voxels per second must be analyzed during a single act of hearing, speaking or reading.
This screams for computational tools, able to handle such large amount of data. In my work, I use tools that have been developed for statistical learning, like predicting the weather, to learn how voxels behave for language. By investigating how voxels encode linguistic units, I hope to help formulate models of spoken communication that can have a direct impact to understand the neural circuitry for speech and language and to help unravel how these circuits fail during speech and language disorders. There is a long road to walk, but with the help of parallel technological development, this road may now be driven in a fast sport car rather than by foot. In 2010, I counted on voxels of 42 cubic millimeters, in 2014 of 8 cubic millimeters, and now in 2016 of 1 cubic millimeter. This increase in spatial resolution has a huge impact on our research, that goes hand in hand with innovation. Together, the vastness of the human brain is becoming increasingly understood.
Post written by Joao Correia, M-BIC, Maastricht University
With love for Research,