Tag Archives: white matter

White matter density in our brains at birth may influence how easily we learn to understand and use language

New research at the University of Boston found that the brain structure of babies can have an important effect on their language development within the first year of life. The findings show that, although nurture plays a vital role in the development of an infant’s language abilities, natural factors also matter.

Image via Pixabay.

The study followed dozens of newborns over the course of five years, looking to establish how brain structure during infancy relates to the ability to learn language during early life. While these results definitely show that natural factors influence said ability, they’re also encouraging — upbringing, or nurture, has a sizable influence on a child’s ability to develop their understanding and use of language.

For the study, the authors worked with 40 families to monitor the development of white matter in infants’ brains using magnetic resonance imaging (MRI). This was particularly difficult to pull off, they explain, as capturing quality data using an MRI relies on the patient keeping completely still.

Born for it

“[Performing this study] was such a fun process, and also one that calls for a lot of patience and perseverance,” says BU neuroscientist and licensed speech pathologist Jennifer Zuk, lead author of the study. “There are very few researchers in the world using this approach because the MRI itself involves a rather noisy background, and having infants in a naturally deep sleep is very helpful in accomplishing this pretty crazy feat.”

The fact that babies have an inborn affinity for absorbing and processing information about their environment and the adults around them isn’t really any news. Anyone who’s interacted with an infant can hear the hints of developing language in their cries, giggles, and myriads of other sounds babies produce.

But we also like to talk to babies, thus helping them understand language better. The team wanted to determine how much of an infant’s ability to learn is due to their inborn traits, and how much of it comes down to the practice they get with the adults in their lives.

The new study reports that functional pathways in the brain play a large role in forming a child’s language-learning abilities during the first year of their life. These pathways are represented by white matter, the tissue that acts as a connector in the brain and links together areas of gray matter, where neurons reside and perform the actual heavy lifting in our brains. The team was interested in white matter in particular as it is the element that actually allows neurons to work together to perform tasks. The practice of any skill leads to the reinforcement of connections that underpin it, they explain, showcasing the importance of white matter in brain functionality.

“A helpful metaphor often used is: white matter pathways are the ‘highways,’ and gray matter areas are the ‘destinations’,” says Zuk.

Together with senior author Nadine Gaab from Boston Children’s Hospital, Zuk met with 40 families with infants to record the development of their white brain matter. In order to ensure the quality of the recorded data, they had to make sure that the babies were sound asleep before placing them in the MRI machine — which was quite a challenge, as these devices can become quite loud. This is the first time researchers have monitored the relationship between changes in brain structure over time and the development of language throughout the first few years of children’s lives.

One area they studied, in particular, is the arcuate fasciculus, a strip of white matter that connects two regions of the brain responsible for the understanding and use of language. MRI machines can determine the density of tissues (in this case, of white matter pathways) by measuring the behavior of water molecules through individual pieces of tissue.

Five years after first peering into the babies’ brains, the team met up with the families again, in order to assess each child’s language abilities. They tested for vocabulary knowledge, their ability to identify sounds within individual words, or to form words from individual sounds.

They report that children born with higher levels of white matter organization showed better language skills at the five-year mark, suggesting that biological factors do have an important role to play in the development of language skills. By itself, however, these results are not enough to prove that biological factors outweigh nurture completely. They’re simply an indication that brain structure can predispose someone towards greater language abilities. The findings are meant to be a piece of a much larger image and not the whole.

“Perhaps the individual differences in white matter we observed in infancy might be shaped by some combination of a child’s genetics and their environment,” she says. “But it is intriguing to think about what specific factors might set children up with more effective white matter organization early on.”

Even if the foundation for language skills is established in infancy, the team explains, our upbringing and experiences are critical to build upon this natural predisposition and play a very important role in a child’s outcome. Judging from the findings, however, the first year of a child’s life is a very good time to expose them to language in order to promote the development of this skill in the long term.

The paper “White matter in infancy is prospectively associated with language outcomes in kindergarten” has been published in the journal Developmental Cognitive Neuroscience.

Fungus-derived molecule enables axon regrowth — potentially treating brain and spinal chord injuries

One family of proteins that plants use to combat fungal infections could have an unexpected use: repairing axons — the long thread-like parts of a nerve cell.

Fluorescent bundles of axons.
Image credits Minyoung Choi / Wikipedia.

Axons are the large projections that neurons use to ferry signals to other parts of the body. They’re the main component of white matter, and without them, the nervous communication in the body would grind to a halt. Axonal damage can also lead to a host of disabilities associated with conditions such as spinal cord injury or stroke.

Andrew Kaplan, a PhD candidate at the Montreal Neurological Institute and Hospital of McGill University, was trying to find a substance that could help undo the damage for people suffering these conditions as part of Dr. Alyson Fournier’s team, professor of neurology and neurosurgery and senior author on the study. During his research, he found one family of proteins with neuroprotective functions known as 14-3-3 which could hold the key to creating axon-repairing drugs.

This family of proteins takes on a surprising role in plants which are fighting off a certain fungal strain. The fungus releases a marker molecule called fusicoccin-A. When exposed to this molecule, the plants’ leaves will wilt but their roots grow longer. This happens because fusicoccin-A affects 14-3-3’s normal interaction with other proteins, promoting growth.

“While 14-3-3 is the common denominator in this phenomenon, the identity of the other proteins involved and the resulting biological activities differ between plants and animals,” says Kaplan.

Kaplan’s theory was that fusicoccin-A could be used to harness 14-3-3 for use in repairing axons. He and his team placed mechanically damaged neurons in a culture with the substance and waited to see what happened.

“When I looked under the microscope the following day the axons were growing like weeds, an exciting result that led us to determine that fusicoccin-A can stimulate axon repair in the injured nervous system,” says Kaplan.

Beyond brain or spinal chord injuries, axonal damage also plays a central role in other disorders and diseases, such as multiple sclerosis or neurodegenerative conditions. Fusicoccin-A and similar molecules could become the starting point for a new class of drugs to treat and repair this damage. Kaplan says future research should aim to better understand the underlying mechanism by which fusicoccin-a improves axonal repair, which can be used to develop even more powerful medication.

One protein called GCN1 holds particular promise. The team found that GCN1 and 14-3-3 bonding can be an important factor in the fusicoccin-A-induced growth.

“We have identified a novel strategy to promote axon regeneration with a family of small molecules that may be excellent candidates for future drug development,” says Fournier.

“This is an exciting advance because the field has struggled to find treatments and identify targets for drugs that stimulate axon repair.”

The full paper “Small-Molecule Stabilization of 14-3-3 Protein-Protein Interactions Stimulates Axon Regeneration” has been published in the journal Neuron.



How the human brain differs according to sex – male and female brains compared

I recently came across a very interesting piece in the NY Post which cites a study that shows that while it was well known that a difference in size between male and female brains exists, there is now evidence that there are significant differences in the size of certain structural parts of the brain, according to gender.

As such, researchers have found, for instance, that  a female’s frontal lobe, responsible for problem-solving, is larger than in a man. Meanwhile, a male’s amygdala, which regulates sexual behavior and “fight or flight” reaction, is bigger.

Men have 9% bigger brains, even after correcting for body size. But men and women share the same amount of neurons, they're just more densely packed in a woman's brain. Click for detail view.

Surprisingly, for me at least, it seems in male brains, men have six and a half times more gray matter than women do. Gray matter is partly responsible for information processing, so may explain in general men tend to be better in math.

As for women, it seems human females have 10 times as much white matter — the part of the brain that’s I partially responsible for connecting information processing centers. This could contribute to the stereotype that why women are good multi-taskers.

Women are thought to have 10 times the amount of "white matter" than men. Some researchers believe that it might play a role in why women often excel at language and verbal skills. But, like the gray matter hypothesis, these are controversial conclusions. Click for detail view.

Of course, this doesn’t prove anything. This doesn’t mean men are smarter than women, just because their brains are bigger, or that women will always be more detail orientated than men and so on. Quality is not proven by size, like in most aspects of life. Hormones, genetic different and more add to the puzzle that compose the human brain, be it man or woman, but this particular research remains very interesting, still.

You can read the hypothesis in greater detail here. I’d love to hear some thoughts on this very controversial piece.