Scientists claim they can now read human mind via fMRI

Scientists have developed a new 'mind reading' artificial intelligence system that can decode complex human thoughts by measuring brain activity.

The researchers at Carnegie Mellon University in the US have been working on is a system that can apparently read complex thoughts based on brain scans, possibly even interpreting complete sentences.

This involved gathering data from a functional magnetic resonance imaging (fMRI) machine, and then using AI machine learning algorithms to pinpoint - and sometimes reverse-engineer - the building blocks the brain uses to construct complex thoughts.

The AI system indicates that the mind's building blocks for constructing complex thoughts are formed by the brain's various sub-systems and are not word-based.

''We have finally developed a way to see thoughts of that complexity in the fMRI signal. The discovery of this correspondence between thoughts and brain activation patterns tells us what the thoughts are built of,'' said Marcel Just from CMU.

In the CMU study, the team was able to demonstrate different brain activations being triggered according to 240 complex events, ranging from individuals and settings to types of social interaction or physical actions. Using the smart algorithm, the team could discern what the person was thinking about at any given time - and even the order of a particular sentence.

After training the algorithm on 239 of the 240 sentences and their corresponding brain scans, the researchers were able to predict the final sentence based only on the brain data.

They were able to do this with an impressive 87 per cent accuracy, as well as doing the opposite: being given sentence information and then outputting an accurate image of how the brain would be activated during that sentence.

Researchers demonstrated that the brain's coding uses an alphabet of 42 meaning components, or neurally plausible semantic features. These consist of feature like person, setting, size, social interaction and physical action. Each type of information is processed in a different brain system – which is how the brain also processes the information for objects, researchers said. By measuring the activation in each brain system, the programme can tell what type of thoughts are being contemplated.

''One of the big advances of the human brain was the ability to combine individual concepts into complex thoughts, to think not just of 'bananas,' but 'I like to eat bananas in evening with my friends,''' Just said. ''Our method overcomes the unfortunate property of fMRI to smear together the signals emanating from brain events that occur close together in time, like the reading of two successive words in a sentence.

''This advance makes it possible for the first time to decode thoughts containing several concepts. That's what most human thoughts are composed of,'' Just added.