Dr Marcin Szwed, a recipient of a Foundation for Polish Science HOMING PLUS programme award, has teamed up with French scientists to prove that the science of reading can entirely programme the cells of the human brain.
Experiments using imaging and clinical cases show us that brain activity is based on specialisations. Some parts of the brain “switch on” when we see faces, and others when we are watching a ball rolling on grass or notice a bus arriving. We also know that a stroke can cause its victim to entirely lose the ability to recognise faces, including those of loved ones. Yet many researchers ask whether these specialisations are innate.
“To test this, it is good to focus on specialisations which cannot be innate. Recognising faces is an evolutionally ancient ability which apes and other animals also possess, but reading was invented just five and a half millennia ago. That’s definitely too short time for evolution to have formed a reading centre in the brain,” explains Dr Marcin Szwed of the Jagiellonian University’s Institute of Psychology, a specialist in reading mechanisms.
Until recently it was not known whether the part of the brain responsible for reading specialises in perceiving letters or also deals with recognition of objects more generally – although in favour of the latter was the fact that in illiterate people this area is responsible for perceiving objects. For several years, researchers have been investigating whether learning to read caused a complete change in the function of the area whose task it was to recognise objects to one of recognising words, but most brain-imaging techniques are too imprecise to test such a small part.
Clinical cases have now been able to help in solving this problem. The neurological clinic in Grenoble, France treats patients with extremely severe cases of epilepsy – so severe that an operation is required. Patients have an electrode implanted to their brains for a week to locate the epileptic centres precisely.
“As the electrodes are placed deep within the brain, they are many times more sensitive than other techniques,” explains Dr Szwed. “Patients spend a week in hospital, getting bored and waiting for their next epileptic fit. They are happy to participate in psychological studies, especially when they are easy, pleasant and involve watching pictures shown on a computer screen.”
The dozens of patients operated on in the Grenoble clinic included two female patients with the initials CQ and PM, who had the electrodes fitted exactly in the area responsible for the ability to read. The French team led by Dr Jean-Philippe Lachaux was able to persuade them to participate in the experiment, and Dr Marcin Szwed was invited to work with them as an expert in reading mechanisms.
The results of the experiment showed that, contrary to what was originally thought, the reactions of the reading area are as “pure” as they could be – this shows that the nerve cells in this area “responded” solely when the patients saw words, but did not react to faces, animals, road signs or even fruit, although the subjects’ task was to press a button when they saw a piece of fruit among other pictures.
“At first I didn’t believe the results myself. I’d never seen responses like them in my life,” says Dr Szwed. “This means that strongly specialised areas in the human brain can also occur as a result of the cultural processes of learning, and the flexibility of the human brain is still underestimated.”
An article describing the experiment appeared in the latest issue of the prestigious American journal Neurology (www.neurology.org, 5 February 2013 issue).
Dr Marcin Szwed returned to Poland after ten years in research centres in Israel and France as a result of grant obtained from the Foundation for Polish Science’s HOMING PLUS programme. The funding allowed the young researcher to carry out the project “Is perception of stimuli permanently assigned to specific areas of the brain such as the visual cortex and motor cortex? fMRI studies among seeing people who also read Braille questions the classic model of the functioning of the brain”. Dr Szwed wants to prove through his research that the area of the visual form of a word is processed by reading by touch in seeing people too, and to show that the various areas of the brain are not assigned in advance to processing information from only one specific sensory modality (e.g. touch, hearing, sight), but are more flexible than previously thought.
Photo: the brain of one of the patients; visible are the electrodes implanted in it. The left-hand one passes right through the reading area of the brain.