Tag: 22/2/23

Categories : NeurologyTags : Leave a comment

During Speech, The Corpus Callosum Hushes the Right Hemisphere

On By ModernMedia
Source: Pixabay

A study published in PLoS ONE has confirmed the role of the corpus callosum in language lateralisation, ie the distribution of language processing functions between the brain’s hemispheres. To get to this finding, the researchers applied advanced neuroimaging methods to study subjects performing an innovative language task for their study.

Functional asymmetry between the two cerebral hemispheres in performing higher-level cognitive functions is a major characteristic of the human brain. For example, the left hemisphere plays a leading role in language processing in most people. However, between 10% and 15% of people also use the right hemisphere to varying degrees for the same task.

Traditionally, language lateralisation to the right hemisphere was explained by handedness, as it is mainly found in left-handed and ambidextrous (using both hands equally well) individuals. But recent research has demonstrated a genetic difference in the way language is processed by left-handed and ambidextrous people. In addition to this, some right-handed people also involve their right hemisphere in language functions.

These findings prompted the scientists to consider alternative explanations, especially by looking at brain anatomy to find out why language functions can shift to the right hemisphere. Researchers at the HSE Centre for Language and Brain hypothesised that language lateralisation may have something to do with the anatomy of the corpus callosum, the largest commissural tract in the human brain connecting the two cerebral hemispheres.

Tractography of the corpus callosumDo Tromp et al. / brainimaging.waisman.wisc.edu

The researchers asked 50 study participants to perform a sentence completion task. The subjects were instructed to read aloud a visually presented Russian sentence and to complete it with an appropriate final word (eg ‘Teper’ ministr podpisyvaet vazhnoe…‘ – ‘Now the minister is signing an important …’). At the same time, the participants’ brain activity was recorded using functional magnetic resonance imaging (fMRI). Additionally, the volume of the corpus callosum was measured in each subject.

A comparison between the fMRI data and the corpus callosum measurements revealed that the larger the latter’s volume, the less lateralisation of the language function to the right hemisphere was observed. 

When processing language, the brain tends to use the left hemisphere’s resources efficiently and the corpus callosum suppresses any additional involvement of the right hemisphere. The larger a person’s corpus callosum, the less involved their right hemisphere is in language processing (and vice versa). This finding is consistent with the inhibitory model suggesting that the corpus callosum inhibits the action of one hemisphere while the other is engaged in cognitive tasks.

The study’s innovative design and use of advanced neuroimaging have made this conclusion possible. Brain lateralisation in language processing is usually hard to measure accurately, as typical speech tasks used in earlier studies (eg image naming, selecting words that begin with a certain letter or listening to speech) tend to cause activation only in some parts of the brain responsible for language functions but not in others. Instead, we developed a unique speech task for fMRI: sentence completion, which reliably activates all language areas of the brain.

The researchers reconstructed the volume and properties of the corpus callosum from MRI data using an advanced tractography technique: constrained spherical deconvolution (CSD). This is more suitable than traditional diffusion tensor imaging for modelling crossing fibres in the smallest unit of volume, the voxel (3D pixel), and is therefore more reliable.

Source: National Research University Higher School of Economics

Categories : PaediatricsTags : Leave a comment

Third of Parents Unnecessarily Use Antipyretics to Reduce Fevers

On By ModernMedia
Source: Cottonbro on Pexels

A new poll done in the US suggests that some parents may not be properly measuring or responding to elevated temperatures in children, and are unnecessarily using antipyretics to bring down their temperatures.

While most parents recognise that a low-grade fever helps a child’s body fight off infection, one in three would give fever-reducing medication for spiked temperatures below 38°C (which isn’t recommended) according to the C.S. Mott Children’s Hospital National Poll on Children’s Health at University of Michigan Health.

Half of parents would also use medicine if the fever was between 38 and 38.9°C, and a quarter of parents would likely give another dose to prevent the fever from returning.

“Often parents worry about their child having a fever and want to do all they can to reduce their temperature. However, they may not be aware that in general the main reason to treat a fever is just to keep their child comfortable,” said Mott Poll co-director and Mott pediatrician Susan Woolford, M.D.

“Some parents may immediately rush to give their kids medicine but it’s often better to let the fever runs its course. Lowering a child’s temperature doesn’t typically help cure their illness any faster. In fact, a low-grade fever helps fight off the infection. There’s also the risk of giving too much medication when it’s not needed, which can have side effects.”

The report is based on 1,376 responses from parents of children ages 12 and under polled between August and September 2022.

Two in three parents polled say they’re very confident they know whether their child needs medication to reduce a fever. But just over half are sure they understand how temperature readings can change according to the method used.

The method used to take a child’s temperature matters and can affect the accuracy of the measurement, Woolford notes. Parents polled most commonly take their child’s temperature by forehead scan or mouth while less than a sixth use ear, underarm or rectal methods.

Remote thermometers at the forehead or inside the ear canal can be accurate if used correctly. But forehead readings may be inaccurate, Woolford says, if the scanner is held too far away or if the child’s forehead is sweaty. With ear thermometers, which aren’t recommended for newborns, earwax can also interfere with the reading.

For infants and young children, rectal temperatures are most accurate. Once children are able to hold a thermometer in their closed mouth, oral temperatures also are accurate while armpit temperatures are the least accurate method.

“Contact thermometers use electronic heat sensors to record body temperature but temperatures may fluctuate depending on how it’s measured,” Woolford said.

“Regardless of the device used, it’s important that parents review the directions to ensure the method is appropriate for the child’s age and that the device is placed correctly when measuring temperature.”

Three in four parents say they take their child’s temperature as soon as they notice a possible problem, while a little less than a fourth wait to see if the problem continues or worsens before taking the temperature.

Two-thirds of parents also prefer to try methods like a cool washcloth before using fever-reducing medication. Most parents also say they always or usually record the time of each dose and re-take their child’s temperature before giving another dose.

“A quarter of parents would give their child more medicine to prevent a fever from returning even though it doesn’t help them get better,” Woolford said. “If a child is otherwise doing well, parents may consider monitoring them and using alternative interventions to help keep them comfortable.”

However, if a newborn or infant less than three months old has a fever, they should immediately see a health professional, Woolford adds.

Source: Michigan Medicine – University of Michigan