Language Ability Equally Affected By Nature And Nurture

Genetic and environmental factors have an equally strong influence on a pattern of brain activity associated with language ability.

AsianScientist (Jan. 6, 2017) – A study in twins has revealed that both environment and genetic background influence language-related brain activities in the left frontal area of the brain. These findings, by researchers from Osaka University, have been published in NeuroImage.

A pattern of brain activity known as even-related desynchronization (ERD) is associated with language processing ability. However, little is known about how genetic and environmental factors affect language-related ERDs. Furthermore, it is not clear how language-related ERDs differ among individuals and how they affect verbal ability.

To resolve these questions, researchers used magnetoencephalography to measure the brain activity of monozygotic (100 percent genetic similarity) and dizygotic (50 percent genetic similarity) elderly Japanese twins. Brain activity was measured while the participants silently read a series of words and generate a verb associated with them. Specifically, the researchers measured ERDs in the 25-50 Hz frequency band in the left frontal area of the brain, a region known to be important for language function.

When ERDs of monozygotic and dizygotic twins were compared, the analyses showed that the power of ERDs is equally affected by genetic and environmental factors. Interestingly, the genetic control of ERDs in the left frontal area was preserved even after the siblings had been living apart for many years. This suggests that genetic factors strongly affected the power of language-specific ERDs.

To determine how language-related ERDs affect verbal ability, the researchers examined correlations between the ERD powers and verbal test scores. Individuals with higher test scores had lower-power ERDs in the left frontal area, showing that verbal memory is associated with language-related ERDs. The authors suggest that the verbal task in this study placed a higher demand on the elderly participants, thereby increasing the power of low gamma ERDs.

The article can be found at: Araki et al. (2016) Language-related Cerebral Oscillatory Changes are Influenced Equally by Genetic and Environmental Factors.


Source: Osaka University; Photo: Pixabay.
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