Study decodes how human brain plans before speaking

New York: A team of US researchers has found pauses in speech in the human brain, which indicates how the complex organ that controls thoughts, memory, and speech, makes plans before speaking.

The team from NYU Grossman School of Medicine analysed brain-mapping recordings of 16 people undergoing surgery to treat seizures related to epilepsy.

The results showed that two regions -- the inferior frontal gyrus and the motor cortex -- in the folded top layers of the brain or cerebral cortex, play an important role in planning before words are said aloud.

Previously, the brain regions were known to control the muscle (motor) movements in the throat and mouth needed to produce speech. It wasn’t clear whether these regions also control “the mix of sounds and words people want to say aloud”, said the team in the paper, published online in the journal Brain.

“Our study adds evidence for the role of the brain’s motor cortex and inferior frontal gyrus in planning speech and determining what people are preparing to say, not just voicing words using the vocal cords or mouthing the words by moving the tongue and lips,” said lead investigator Heather Kabakoff, a speech pathologist at NYU Langone.

The overall findings also confirm that motor execution and speech planning occur in distinctly different brain areas. While more research is needed, the team noted that the study may help “surgeons better refine their brain mapping to protect patients’ speech”.