Tone-deaf people--those who can't hold a tune--appear to be missing a specific neural circuit, according to research published today in the Journal of Neuroscience.

Researchers used a variation of MRI called diffusion tensor imaging to compare neural circuits--specifically those between the right temporal and frontal lobes--in the brains of people who are tone-deaf and those who are not.

According to a press release from the Society for Neuroscience, which published the research,

This region, a neural "highway" called the arcuate fasciculus, is known to be involved in linking music and language perception with vocal production.The arcuate fasciculus was smaller in volume and had a lower fiber count in the tone-deaf individuals. More notably, the superior branch of the arcuate fasciculus in the right hemisphere could not be detected in the tone-deaf individuals. The researchers speculated that this could mean the branch is missing entirely, or is so abnormally deformed that it appears invisible to even the most advanced neuroimaging methods.

Ambient Corporation, a company based in Champaign, IL, that develops communications technologies for people with speaking disabilities, is calling its latest system "voiceless communication" with good reason. The company has engineered a neckband that translates a wearer's thoughts into speech so that, without saying a word, he or she can have a cell-phone conversation or query search engines in public.

Don't fret: the device, called Audeo, can't read minds, so it won't capture your secret thoughts. It picks up the neurological signals from the brain that are being sent to the vocal cords--a person must specifically think about voicing words--and then wirelessly transmits them to a computer, which translates them into synthesized speech. At the moment, the device has a limited vocabulary: 150 words and phrases.

The video below shows Michael Callahan, a cofounder of Ambient and a developer of the device, demonstrating the technology at the Texas Instruments Developers Conference, which was held in Dallas from March 3 through 5. In his speech, he says that by the end of the year, the device will be ready for use by people with Lou Gehrig's disease, a progressive neurodegenerative disease that can cause sufferers to become completely paralyzed. He also says that in the future, if a person is walking down the street thinking about where a bus station is located, the device will automatically wirelessly query a search engine to find one.

Credit: Texas Instruments