Researchers from the HSE Center for Language and Brain have identified previously unknown age-related changes in brain activity throughout the perception of auditory information in a bunch of kids aged 7–12 years. The researchers used magnetoencephalography (MEG), an ultra-precise approach to brain activity recording. The outcomes obtained could be used to explore the impairments in language comprehension in children with autism. The study was published within the Human Brain Mapping.

Neurons are brain cells that communicate with one another via electrical signals. It is understood that while perceiving and processing information (including acoustic information), not only the full electrical activity of neurons is important, but additionally the rhythmic activity of neuron groups in several frequency ranges. Cortical gamma-band oscillations are a style of rhythmic brain activity that play a major role in perception. Gamma rhythms are oscillations within the human brain with frequencies from 30 to 150 Hz.

Previous studies reported difficulties detecting a gamma response in young children. Scientists attribute this to the incontrovertible fact that one of these brain activity is related to the inhibitory system, which matures by puberty and, in consequence, the ability of gamma oscillations increase with age by early puberty in children. Furthermore, gamma rhythms reflect the balance between the neural excitation and inhibition within the brain, so the age-related changes in gamma power indicate the age-related changes of this balance.

Researchers from the HSE Center for Language and Brain investigated the age-related changes within the activity of gamma oscillations within the auditory cortex in 30 typically-developing primary school children (7–12 years old). The researchers used the classical Auditory Regular-State Response paradigm, presenting amplitude-modulated tones on the 40 Hz range. This paradigm enables the recording of the rhythmic activity of neurons within the auditory cortex at a frequency of 40 Hz (i.e., gamma rhythms). To record brain activity the researchers used a singular approach to magnetoencephalography (MEG), which makes it possible to record the full activity of neurons in good temporal and spatial resolutions. In other words, scientists can discover how the signal flows in millisecond resolution and determine the localisation of the source of activity within the cerebral cortex.

The outcomes demonstrated that the ability of gamma oscillations within the auditory cortex modified with age: the ability was higher in older children than in younger ones. As well as, the researchers have shown for the primary time that the cortical localization of this activity can even change with age.

In older children, the source was positioned more posterior in the first auditory cortex than in younger ones. Furthermore, the researchers demonstrated for the primary time that the second style of activity (the full neuromagnetic response to an auditory stimulus) in the identical a part of the brain also modified with age: the amplitude decreased in older children.

Finally, the outcomes showed that the 2 varieties of brain activity were related to one another: the upper the ability of rhythmic activity within the gamma range, the lower the amplitude of the full magnetic response to the stimulus. The researchers imagine that each one these effects are related to age-related changes within the balance between excitation and inhibition.

These age-related changes in various kinds of activity could also be parts of the identical developmental mechanism within the auditory cortex. We expect that it is crucial to grasp all these mechanisms, since in the long run it may contribute to the study of auditory perception in children with atypical development. For instance, numerous studies have revealed atypical functioning of gamma oscillations in children with autism. That is more likely to be one in every of the neurophysiological mechanisms of impairments in language comprehension in such children.”

Vardan Arutiunian, creator of the article and junior research fellow on the HSE Center for Language and Brain

Source:

National Research University Higher School of Economics

Journal reference:

Arutiunian, V., et al. (2022) The age-related changes in 40 Hz Auditory Regular-State Response and sustained Event-Related Fields to the identical amplitude-modulated tones in typically developing children: A magnetoencephalography study. Human Brain Mapping. doi.org/10.1002/hbm.26013.