Reading and white matter in the brain

A new study that focuses on "white matter" finds that learning how to read relies on changes in brain connections.

brain (photo credit: Wikicommons)
(photo credit: Wikicommons)
Learning to read relies on changes in brain connections, according to a newly published study in PNAS, Proceedings of the [US] National Academy of Science. Dr. Michal Ben- Shachar of Bar-Ilan University’s English department and the Gonda (Goldschmied) Multidisciplinary Brain Research Center, is part of a research team that conducted the “unique” study.
Ben-Shachar’s studies focus on “white matter” – a network of pale, myelin-sheathed connections that allows information transfer between distant parts of the brain. She and her fellow researchers use diffusion tensor imaging (DTI) and an MRIbased, non-invasive technique to measure the properties of the white-matter connections and how they change over time. Using DTI the team, led by Stanford University Prof. Brian Wandell, tracked the development of reading skills and white matter connections in 55 children ages seven to 12 over a three-year period and related changes in the brain to changes in reading skill.
“The nice thing about DTI is that it is really child friendly. In a 12-minute scan, you can collect high-quality data from the whole brain, while the child is lying still watching a movie.
At Stanford, we scan children as young as six, and they do this very well,” says Ben-Shachar, who conducted her post-doctoral research at Stanford and continues from Israel to collaborate with two labs there.
The researchers found that high-performing readers initially had lower levels of white matter in the areas of the brain associated with reading, but these levels grew rapidly during the three years studied. By contrast, below-average readers had higher initial levels of white matter in the areas associated with reading, but these levels declined over time, suggesting the children were not creating and strengthening neural pathways.
“This study is unique in its longitudinal aspect. Most developmental imaging studies compare brain measures in groups of children and adults. In contrast, we followed up on the same group of children over a long period of time. By doing so, we discovered that the changes in brain connections are more informative about reading skill than the measurement at a specific point in time,” says the Bar-Ilan researcher.
“This is really important if we are ever going to use MRI as a diagnostic tool in education, in addition to standard behavioral tools. It means we will have to assess the child more than once in order to look at dynamic developmental changes, because change is more important than absolute measures at a particular time point,” she concludes.
In a project awarded a prestigious grant from the Israel Science Foundation, she and Tel Aviv University colleagues Ofer Amir and Ruth Ezrati are looking at white matter pathways in the brains of people who stutter. Separately, she is working with Ethiopian immigrants, for some of whom Hebrew is their first written language, in the hope of identifying how the adult brain changes as literacy is acquired.
Many women who repeatedly suffer from bladder and kidney infections have been drinking cranberry juice regularly in the belief that the acidic liquid prevents them. But now, an independent systematic meta-analysis in The Cochrane Library says that while drinking the juice may treat such infections, it is unlikely to prevent them.
Urinary tract infections (UTIs) affect the bladder, as in cystitis, and sometimes the kidneys. Cranberries and cranberry juice have been used to prevent UTIs for decades, although it is not clear how they might help protect against infection. According to one theory, certain sugars and flavanol compounds in cranberries prevent bacteria sticking to cells lining the walls of the urinary tract.
Several systematic reviews have been published on the subject in The Cochrane Library, each time incorporating more evidence. In the last review in 2008, it was concluded that cranberries offer a small benefit in preventing recurring UTIs in women.
In the current review, the researchers gathered together evidence from 24 studies that involved a total of 4,473 people. These studies included 14 added since the 2008 update. Those in treatment groups were given cranberry juice, tablets or capsules, while those in control groups were given placebo cranberry products, water, methenamine hippurate, antibiotics, lactobacillus or nothing.
Although in some studies there were small benefits for women suffering from recurring infections, women would have to consume two glasses of cranberry juice per day for long periods to prevent one infection.
The researchers conclude that current evidence does not support cranberry juice as a means of preventing UTIs.
“Now that we’ve updated our review with more studies, the results suggest that cranberry juice is even less effective at preventing UTIs than was shown in the last update,” said lead researcher Dr. Ruth Jepson of the University of Stirling in the UK.
In the studies where participants were given juice, there were large numbers of dropouts, suggesting it might not be acceptable to drink over long time periods. A common problem with the studies evaluating cranberry tablets or capsules was that they rarely reported the amount of active ingredient, so it was unclear whether levels would have been high enough to have any effect.
“We can’t see a particular need for more studies of the effect of cranberry juice, as the majority of existing studies indicate that the benefit is small at best, and the studies have high drop-out rates,” said Jepson.
“More studies of other cranberry products such as tablets and capsules may be justified, but only for women with recurrent UTIs, and only if these products contain the recommended amount of active ingredient.”
Cochlear implants do wonders to restore at least some hearing to the deaf or hearing disabled. Now Sheba Medical Center at Tel Hashomer has performed three such operations, inserting electrodes by endoscope instead of drilling a hole in the skull.
Prof. Lala Migirov of Sheba’s earnose- and-throat department said the surgical technique, which was successful, has been performed so far on 10 patients in Chicago.
Using an endoscope improves visibility and makes it more likely the electrodes will be implanted in the proper place without causing damage to the cochlea in the inner ear. It can thus increases the chances for preserving any remnants of hearing in adults.