Neuroscientists may one day be able to hear the imagined speech of a patient unable to speak due to stroke or paralysis, according to University of California, Berkeley, researchers. In this edition of the PLoS Podcast, PLoS Biology Editor Ruchir Shah interviews Brian Pasley and Robert (Bob) Knight from UC Berkeley. Brian is a postdoc in Bob's lab, and Bob is the Director of the Helen Wills Neuroscience Center at Berkeley.Essentially, they were able to decode activity in the human auditory system in order to guess the words that people were actually listening to. This technique, called “stimulus reconstruction”, has received a lot of media attention, particularly due to sensational claims of mind-reading. But in reality, there are some important practical applications of this type of research for neural prosthetics. For patients that can't speak, for example, being able to reconstruct words that they imagine would allow them to communicate through a new interface.In this podcast, Brian and Bob discuss how they were able to reconstruct words using activity in a specific region of the human brain called the superior temporal gyrus, or STG. They then discuss the implications for neural prosthetics, and also the potential ethical implications for “mind-reading”.These scientists have succeeded in decoding electrical activity in the brain’s temporal lobe – the seat of the auditory system – as a person listens to normal conversation. Based on this correlation between sound and brain activity, they then were able to predict the words the person had heard solely from the temporal lobe activity.
“This research is based on sounds a person actually hears, but to use it for reconstructing imagined conversations, these principles would have to apply to someone’s internal verbalizations,” cautioned first author Brian N. Pasley, a post-doctoral researcher in the center. “There is some evidence that hearing the sound and imagining the sound activate similar areas of the brain. If you can understand the relationship well enough between the brain recordings and sound, you could either synthesize the actual sound a person is thinking, or just write out the words with a type of interface device.”“This is huge for patients who have damage to their speech mechanisms because of a stroke or Lou Gehrig’s disease and can’t speak,” said co-author Robert Knight, a UC Berkeley professor of psychology and neuroscience. “If you could eventually reconstruct imagined conversations from brain activity, thousands of people could benefit.”In addition to the potential for expanding the communication ability of the severely disabled, he noted, the research also “is telling us a lot about how the brain in normal people represents and processes speech sounds.”Pasley and his colleagues at UC Berkeley, UC San Francisco, University of Maryland and The Johns Hopkins University report their findings Jan. 31 in the open-access journal PLoS Biology.
Help from epilepsy patients
They enlisted the help of people undergoing brain surgery to determine the location of intractable seizures so that the area can be removed in a second surgery. Neurosurgeons typically cut a hole in the skull and safely place electrodes on the brain surface or cortex – in this case, up to 256 electrodes covering the temporal lobe – to record activity over a period of a week to pinpoint the seizures. For this study, 15 neurosurgical patients volunteered to participate.
An X-ray CT scan of the head of one of the volunteers, showing electrodes distributed over the brain’s temporal lobe, where sounds are processed.
“This research is based on sounds a person actually hears, but to use it for reconstructing imagined conversations, these principles would have to apply to someone’s internal verbalizations,” cautioned first author Brian N. Pasley, a post-doctoral researcher in the center. “There is some evidence that hearing the sound and imagining the sound activate similar areas of the brain. If you can understand the relationship well enough between the brain recordings and sound, you could either synthesize the actual sound a person is thinking, or just write out the words with a type of interface device.”“This is huge for patients who have damage to their speech mechanisms because of a stroke or Lou Gehrig’s disease and can’t speak,” said co-author Robert Knight, a UC Berkeley professor of psychology and neuroscience. “If you could eventually reconstruct imagined conversations from brain activity, thousands of people could benefit.”In addition to the potential for expanding the communication ability of the severely disabled, he noted, the research also “is telling us a lot about how the brain in normal people represents and processes speech sounds.”Pasley and his colleagues at UC Berkeley, UC San Francisco, University of Maryland and The Johns Hopkins University report their findings Jan. 31 in the open-access journal PLoS Biology.
Help from epilepsy patients
They enlisted the help of people undergoing brain surgery to determine the location of intractable seizures so that the area can be removed in a second surgery. Neurosurgeons typically cut a hole in the skull and safely place electrodes on the brain surface or cortex – in this case, up to 256 electrodes covering the temporal lobe – to record activity over a period of a week to pinpoint the seizures. For this study, 15 neurosurgical patients volunteered to participate.
An X-ray CT scan of the head of one of the volunteers, showing electrodes distributed over the brain’s temporal lobe, where sounds are processed.
read more at http://beforeitsnews.com/story/1705/586/NL/
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