Speech Mechanism Decoded
A latest breakthrough on how the brain lets us pronounce vowels could help paralytic patients to learn to talk again. People like physicist Stephen Hawking, who is a victim of motor neuron disease could also be helped to recover speech.
The new discovery by scientists could pave way for prosthetic devices in the brain that could help return the ability to speak in people paralyzed by injury or disease, Mail Online reported.
For the research, scientists observed and studied 11 epilepsy patients with electrodes implanted in their brains in order to find the origin points of their seizures, with neuron activity as they uttered one of five vowels or syllables containing the vowels recorded.
The scientists could zero down to two areas - the superior temporal gyrus and a region in the medial frontal lobe - which consisted neurons related to speech and were in tune with vowels pronunciation.
It was found that neurons in the superior temporal gyrus responded to all vowels, although the rate of firing differed from vowel to vowel. However, neurons in the medial frontal region fired exclusively for only one or two vowels.
"Single neuron activity in the medial frontal lobe corresponded to the encoding of specific vowels," Dr. Itzhak Fried, a professor of neurosurgery at the David Geffen School of Medicine at UCLA was quoted as saying by Science Daily.
"The neuron would fire only when a particular vowel was spoken, but not other vowels."
Overall, the neurons' encoding of vowels in the brain's superior temporal gyrus gave an anatomical picture of how speech was possible-specifically, the tongue's position inside the mouth.
"Once we understand the neuronal code underlying speech, we can work backwards from brain-cell activity to decipher speech," said Fried. "This suggests an exciting possibility for people who are physically unable to speak. In the future, we may be able to construct neuro-prosthetic devices or brain-machine interfaces that decode a person's neuronal firing patterns and enable the person to communicate."
The study was supported by grants from the European Council, the National Institute of Neurological Disorders and Stroke, the Dana Foundation, Lady David and L. and L. Richmond research funds and was published in the journal Nature Communications.