How the brain predicts speech: Key region found that could help create accurate mind-reading devices

• Researchers found a brain region involved in identifying sounds
• It is used to predict upcoming words during conversation
• The region is blocked in people with disorders such as dyslexia and ADHD
• Study authors say that companies like Google and Facebook could one day use the region to  predict user behaviour

Scientists have discovered how the brain helps us to predict what is coming next in speech. The researchers say they have found a key part of the brain involved in identifying sounds that is used to predict upcoming words during conversation 

Scientists have discovered how the brain helps us to predict what is coming next in speech.

The researchers say they have found a key part of the brain involved in identifying sounds that is used to predict upcoming words during conversation.

And companies like Google and Facebook could one day use the technology to create devices that read users' minds, one researcher suggests.

'Google and Facebook are really interested in how your brain makes predictions and learns because they want to use brain signals to control phones or to improve predictions in their software,' study lead author Professor Chris Petkov, a neuropsychologist at Newcastle University, told MailOnline.

'They want to know how they can predict what people do, and how they can then change devices to reflect this. 'Our work shows how this happens in the brain: Neurons make predictions at specific points in time and adjust those predictions when a prediction mistake happens.'

The researchers say that the area they have identified is found within the brain's 'auditory cortex', a region unchanged by evolution for millions of years.

It is inhibited in people with disorders such as dyslexia, schizophrenia and Attention Deficit Hyperactivity Disorder (ADHD). The finding could one day lead to a better understanding and treatment of these conditions, the researchers claim. 'There are groups around the world who could use these findings to see how the brain makes predictions and also how it responds when it is wrong,' Professor Petkov told MailOnline.

'Ultimately we do want to help people who struggle to make predictions, such as those with dyslexia or ADHD, to better make those predictions.

'In some cases we will be at the stage where we can help the brain to recover from these conditions.'

Using an approach developed for studying language learning in children, Professor Petkov and his team had humans and monkeys decode a made-up language.

The groups were played a sequence of sounds or short sentences of words spoken in the language, which has properties and rules that subjects could follow.

The team made their finding by having humans and monkeys decode a made-up language. This image shows the artificial grammar rules of the fake language and the phase-amplitude coupling seen by the team in the human 'auditory cortex' - a key region used to decode sound

Both species were able to learn the predictive relationships between the spoken sounds in the sequences.

Activity in the auditory cortex of the two species revealed how groups of neurons responded to the speech sounds and to the learned predictive relationships between those sounds.

'Even direct recordings from the brain do not give us access to what the neurons are doing, which is why the link to monkeys was so important to establish,' Professor Petkov told MailOnline.

'We see that certain types of neurons are constantly and actively making predictions.

'This occurs shortly before the neurons notice when a prediction mistake has occurred.

'The reason this is important relates to how it could ultimately help people with problems predicting what will happen next. 'For example, scientists can next ask whether one or both types of neuronal predictive responses rely on each other and which might be malfunctioning in people that suffer from different types of disorders.'

The brain responses in monkeys and humans were found to be remarkably similar in both species.

This suggests that the way the human auditory cortex responds to speech has been passed down through a common ancestor, rather than being uniquely specialised in humans for speech or language.

'A number of things were very similar between the monkeys and humans, suggesting a fundamental element to prediction in the brain,' Professor Petkov told MailOnline.

'Being able to predict events is vital for so much of what we do every day.'

Study coauthor Dr Yuki Kikuchi added: 'In effect we have discovered the mechanisms for speech in your brain that work like predictive text on your mobile phone, anticipating what you are going to hear next.

'This could help us better understand what is happening when the brain fails to make fundamental predictions, such as in people with dementia or after a stroke.'

Building on these results, the team are working to understand how predictive brain signals go wrong in patients with stroke or dementia.

The long-term goal is to identify strategies that yield more accurate prognoses and treatments for these patients.