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Cognitive Neuroscience

The New Mind-Readers

Such progress in brain activity scan analysis would take us nearer to decoding the subjective Contents of our thoughts and their patterns. The immediate possibilities of using this technique in criminology is still far ahead, but this does pose an ethical question of a sinister nature. Aren’t our thoughts our own private things? This disturbing facet has been doing the rounds in some circles, as these results are being discussed. But ultimately, the responsibility lies with us. In any case, these are exciting times to unravel the secrets of the mind.

Key Points

- A functional MRI scan has successfully interpreted neural responses to a specific visual stimulus.
- It can detect activity even when the subject is not conscious of the stimulus.
- The implications of this research raise several ethical questions.

Garga Chatterjee, a physician and researcher at the department of neurology, Kolkata Medical College, reports on the frontiers of cognitive neuroscience, where research suggests that specialised MRI scans can interpret responses to different visual stimuli.

Mind-reading might sound like sci-fi stuff.Not any more, if indications from studies by two groups from Vanderbilt University, Nashville, Tennessee and University College London are taken into account.Studies from these groups have taken mind-reading from the realm of sci-fi to hard science.

I Can See What You See

Cognitive Neuroscience In a study published in Nature Neuroscience (May 2005), Dr Yukiyasu Kamitani of ATR Computational Neuroscience Laboratories, Kyoto, Japan and Dr Frank Tong of Princeton University (now at Vanderbilt), showed parallel lines of eight different orientations to the subjects. Each of these eight different orientations produced neural activity in the brain. As the subjects were looking at these lines, they were being simultaneously scanned in a specialised MRI scanner, a technique known as functional MRI (fMRI). The scans showed the activation of visual areas as would be normally anticipated.

What this duo have accomplished is astonishing. They have written a program that can tease out orientation-specific information about the orientations being shown at that time, and hence predict the stimulus (orientation of the parallel line) with accuracy. What this study did was to predict which of the eight orientations was being shown at a given point in time. Now, think of that. Let’s say you were shown the picture of a cat and then the picture of a dog. What this study says is that it’s possible just by specialised analysis of your brain scan as you were looking at the pictures to determine whether you were looking at a cat or at a dog.

Are you thinking what I’m thinking?

However, that’s not the end of the story. In the same paper they report another experiment of even greater significance. In this experiment, parallel lines of two different orientations were superimposed on each other and the subjects were told to pay attention very carefully to one of them, that is, to concentrate very hard on one. Neural processes like attention modulate the way visual information is processed. As before, the subjects were scanned during this activity. The research team analysed the scans and could predict which of the two orientations the subject was concentrating on. This is like telling you ‘I know what you are thinking’. Very spooky indeed!

This study actually distinguishes between what was shown (the two sets of superimposed orientation lines) and what was seen (the attendant orientation set). In fact, the far-reaching effects of this technology were quickly acknowledged, as Dr Frank Tong was named one of the 50 innovators of the year by Scientific American.

Decoding the Subconscious

The work by Dr Geraint Rees and DrJohn Dylan Haynes of University College London takes it further. In another study published in Nature Neuroscience, they report decoding information from the brain that the person in question is not even aware of. Dr John Dylan Haynes and Dr Geraint Rees showed a set of oriented lines to the subject, but only very briefly. The exposure was too short for the subjects to be consciously aware of the orientation shown. This was followed by another pattern which was the ‘mask’ and which the subjects consciously perceived. In this visual illusion, the subjects cannot describe what they first saw. They do remember the second, which is the masking stimulus.That the subjects cannot remember or guess the orientation that was briefly shown to them is one thing. But the visual stimuli did register in the subject’s brain. The study indicates that the V1 columns of the primary visual cortex of the subject brains did register this information, although this information was not available to the subject’s consciousness. This is a crucial dissociation.

This raises questions as to whether the conscious mind or the awareness module have access to this information, which is there in V1 columns. And just how do we know that the information was there? Using a technique similar to that used by Dr Tong’s group, the UCL group could predict well above chance by analysing the brain scans of the subjects, which stimulus the subject was shown before the mask. Dr Rees says that the two experiments (his and Dr Tong’s) show that neuronal activity in V1 is necessary but not sufficient for the mind to be aware of the orientation data it holds. By analysing functional MRI data of brain activity, the UCL group could thus make out which image had been shown, when even the subjects themselves report not being able to remember seeing it. The results show how the brain reacts to visual stimuli, even in cases when they are ‘invisible’ to our conscious mind.

Fascinating Implications

The implications of this study combined with others of the same kind are tremendous. So, a brain (the experimenter’s) can know more about the state of another brain (the subject’s) than the subject knows. Information that the subject is not aware of can be available to others. This is very different from a physician looking at a scan and saying that one has had a stroke. There is no prediction of real-time perception involved.

So, to see ourselves as others see us. That is the tantalising promise of cognitive neuroscience.

Such progress in brain activity scan analysis would take us nearer to decoding the subjective Contents of our thoughts and their patterns. The immediate possibilities of using this technique in criminology is still far ahead, but this does pose an ethical question of a sinister nature. Aren’t our thoughts our own private things? This disturbing facet has been doing the rounds in some circles, as these results are being discussed. But ultimately, the responsibility lies with us. In any case, these are exciting times to unravel the secrets of the mind.