Learning new speech movements or relearning speech after injury requires coordinated mouth and face movements. These depend on brain networks that include orofacial sensory systems (input from lips, tongue and jaw) and motor systems that move the muscles.
A team led by Yale researchers tested which brain areas support memory for newly learned speech patterns. Participants heard their own speech altered in real time through headphones, which caused speech motor learning. The researchers then applied transcranial magnetic stimulation (TMS) to the auditory cortex, the somatosensory cortex, or the motor cortex.
They tested retention 24 hours later. Disrupting activity in the auditory or somatosensory cortex made it harder for participants to retain the new speech changes, while disrupting the motor cortex did not reduce retention. The authors say this shows that sensory brain changes are necessary for learning and keeping new speech movements. The finding has clear implications for rehabilitation after stroke and for speech technologies.
Difficult words
- coordinated — working together in a smooth, organised way
- orofacial — related to the mouth and face area
- sensory — connected with senses like touch or hearing
- motor — related to movement and muscles
- auditory cortex — brain area that processes sound information
- somatosensory cortex — brain area that receives touch and body signals
- motor cortex — brain area that controls muscle movement
- transcranial magnetic stimulation — a noninvasive method to change brain activity
- retention — the ability to keep new information or skills
- rehabilitation — medical support to help people recover skills
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How might this study change the way therapists help people relearn speech after a stroke or injury?
- What concerns or benefits do you see in using brain stimulation methods like transcranial magnetic stimulation for therapy?
- How could speech technology developers use the finding that sensory brain changes help keep new speech movements?
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