The left hemisphere processes auditory speech information more rapidly.
Turns out, the left side of one's brain can comprehend linguistic skills better than the right.
According to a research at Ruhr University synapses are vital for rapid processing of auditory speech, which is found to be more in the left hemisphere of planum temporal as compared to the right. Therefore, the left hemisphere has dominance over the language.
A deep look into the microstructure of planum temporale with the speed of auditory speech processing has now become possible with the help of a new form of magnetic resonance imaging (MRI) in combination with electroencephalography (EEG).
It is learned that when brainwaves are measured using EEG, the left hemisphere processes auditory speech information more rapidly.
Under an experiment by the researchers, when playing two different syllables - for example 'Da' and 'Ba' - to a person's left and right ear via headphones, most people stated that they only heard the syllable in the right ear. This was because language perceived via the right ear is processed in the left hemisphere.
"However, it had previously not been understood if that asymmetrical microstructure is the decisive factor for the superiority of the left hemisphere when it comes to the processing of auditory speech," added Erhan Genç, a researcher.
The method for counting the number of neural synapses in living humans is yet not discovered, and thus, could not be conclusively linked to the performance of auditory speech processing.
The researchers have now closed this gap with the aid of so-called neurite orientation dispersion and density imaging.
Due to the instalment of highly specific MRI technology, the bio-psychologists were able to measure the density and spatial arrangement of planum temporale neurites in almost one hundred test participants.
The EEG measurements were simultaneously used to analyse the processing speed of auditory speech information in both the left and the right hemispheres in them.
The research resulted in a conclusion that test participants who were capable of processing auditory speech in the left hemisphere at a high speed possessed an extraordinarily high number of densely packed neurites in the left planum temporale.
The findings are published in the scientific journal Science Advances.