By Andy Ho, Senior Writer
IF WE could read minds, most cases in court would be quickly sewn up and justice expeditiously served.
In fact, in some courts, neuroscience evidence has already been offered and accepted as being - in some attenuated sense - revelatory of one's thoughts. In June 2008, a Mumbai judge relied upon the Brain Electrical Oscillations Signature (Beos) test to convict a woman of murdering her fiance.
The Beos test consists of conventional electroencephalography (EEG) - electrical signals detected on the scalp when neurons within the brain fire away - analysed using some computer software.
In its written judgment, the court offered a lengthy apologia for using this relatively untested and unreliable technology.
Some practitioners now prefer EEG-fMRI, which is EEG being recorded at the same time as when a functional magnetic resonance imaging (fMRI) scan is performed. But it is fMRI itself that has become neuroscience's pin-up model.
There is now published research on using this neuroimaging technique to identify which brain areas are fired up by hypnosis, erotic thoughts, deep meditation, mathematical manipulation and so on.
Subjects are made to lie down in an MRI scanner and asked to think about, look at or listen to something while the scanner looks for changes in the flow of blood with lots of or little oxygen to specific parts of the brain.
The scanner's pictures of the brain are divided into little cubes called 'voxels'. The number of voxels with oxygenated and deoxygenated blood is counted and the ratio calculated.
It is thought the brain areas where neurons have just fired off will receive an inflow of oxygen-rich blood just a few seconds after. Measuring the ratio of oxygenated to deoxygenated voxels supposedly shows which brain areas are most active during a particular mental activity. As there is a lot of 'noise' in voxel measurement, computerised statistical packages are used to analyse the data.
[Click here to read full article]
No comments:
Post a Comment