Posted November 26, 2014
Your brain turns sounds into words instantaneously. Researchers at the University of California, San Francisco, studied the areas of the brain that recognize speech and discovered several amazing features.
Sounds outside the brain are received and transferred into four regions, where they are processed into recognizable words:
- Auditory cortex – Sounds entering through the ears are converted into impulses and sent to the auditory cortex located on both sides of the brain.
- Wernicke’s area – Next, the sounds move into the Wernicke’s area, located on the left side of the brain, where impulses are turned into words and phrases.
- Broca’s area – After words are formed, a response is created in the Broca’s area, also located in the left hemisphere.
- Motor cortex – As words are created and phrases formed, the motor cortex assists with articulating the ideas, and work with the vocal cords to produce actual sounds.
Researchers studied the brain activity of six people in a hospital who allowed surgeons to place a recording device on the surface of their brains. They were surprised to discover that brain cells responded to basic phonemic features (distinctive sounds created by the lips, tongue or vocal cords) vs. just the phonemes (sounds that distinguish words). For example:
- Some brain cells respond specifically to plosives, such as the “puh” sound in the word peppers.
- Other neurons react to fricative consonants, such as the “f” sound in the word Friday.
Researchers believe this study provides insights into understanding challenges for people who struggle with speech impairment. It also reveals possibilities to improve voice recognition features of electronic machines and tools, such as smartphones.