The human brain is perhaps the most complex thing we have ever known. The more we explore it, the more there is to explore. Scientists have been long baffled about how our brain processes thing. While a lot is now known, thanks to the research in this field, a lot still need to be explored. A study at the Georgetown University Medical Center (GUMC) reveals how our brain processes words. The results of the study were published in the Journal of Neuroscience. It says that when we look at a known word, our brain doesn’t see it as a group of letters that need to be processed; instead it sees it like a picture. The study at GUMC also shows that the brain learns words quickly by tuning neurons to respond to a complete word, not parts of it.
Maximilian Riesenhuber, PhD, who leads the GUMC Laboratory for Computational Cognitive Neuroscience and who is also the study’s senior author says that neurons can differentiate between real words and words that make no sense. For example, it can differentiate ‘turf’ from ‘turt’ (which is no word actually). There is a small area of the brain that is ‘holistically tuned’ to recognize complete words.
There have been previous studies which had suggested that we might be recognizing words by quickly spelling them out or identifying parts of words. But, this study has a totally new take on how our brain processes words. Neurons in a small brain area remember how the whole word looks – it is something akin to a visual dictionary says Riesenhuber.
This part of the brain which is dubbed as the visual dictionary is called the visual word form area; it is situated in the left side of the visual cortex. It is just situated opposite from the fusiform face area on the right side, which remembers how faces look. Riesenhuber says while one area is selective for a whole face and allows us to quickly recognize people, the other is selective for a whole word, and helps us read quickly.
For this study 25 adult participants were asked to learn a set of 150 fake or nonsense words. With the help of functional magnetic resonance imaging (fMRI), the brain plasticity associated with learning was investigated, both before and after training.
A specific fMRI technique known as fMRI-rapid adaptation was used to investigate the changes in the word form area of the brain. It was found that the brain responded to the fake words like nonsense words before the participants learnt it. But, after training the neurons responded to the learned words like they were real words. Laurie Glezer, PhD the study’s lead author says that this study is the first of its kind to show how neurons change their tuning with learning words and it demonstrates the brain’s plasticity.
Riesenhuber opined that these findings don’t just help in revealing how the brain processes words, but it also provides insights into how to help people with reading disabilities. He adds that for people who cannot learn words by spelling them out, learning the whole word as a visual object can be a good strategy. Riesenhuber also added that when their first groundbreaking study on the visual dictionary was published in Neuron in 2009, they were contacted by a number of people who had been through reading difficulties and they said that learning word as visual objects helped a great deal.
Riesenhuber also revealed that the visual word form area in the brain does not care how the word sounds, what matters is just how the letters of the word look together. He also added since this kind of learning happens only in a small part of the brain, it is a good example of selective plasticity in the brain.