Secret fantasies no longer secret By Zakiyah Fallata JEDDAH - For the first time, scientists may find a way to read people's thoughts by using Magnetic Resonance Imaging (MRI). A group of American researchers from University of California (UC), Berkeley, could read thoughts and decode their serials after they identified the images which were depicted on volunteers. The researchers have observed patterns of brain activity and analyzed the signals that came out from the brain when a subject examined a range of black and white photographs, and then decoded them using the magnetic technique. The technique relies on functional magnetic resonance imaging (fMRI), a standard technique that creates images of brain activity based on changes in blood flow to different brain regions Magnetic resonance imaging (MRI) is primarily used in medical imaging to visualize the structure and function of the body. It is also used to measure the levels of different metabolites in body tissues. The MR signal produces a spectrum of resonances that correspond to different molecular arrangements of the isotope being “excited”. This signature is used to diagnose certain metabolic disorders, especially those affecting the brain. Scientist, led by Jack L. Gallant, an Associate Professor of Psychology and Vision Science from UC at Berkeley said that their goal of experiment was to design a process for decoding information from human visual cortex. “Our procedure depended on using functional magnetic resonance imaging (FMRI) for measuring brain activity as a person looked at randomly chosen thousands photographs.”, Said Gallant. Using those data, the researchers tried to develop to develop a computational model that could predict the pattern of brain activity that would be elicited by any arbitrary photograph. However, researchers used FMRI to measure brain activity elicited by a second randomly chosen set of photographs, which is completely distinct from the first set. They eventually used the computational model to identify, from brain activity alone, which specific image in the second set the person saw at each point in time. Based on a mode analogous to the classic card trick of a magician, “pick a card, any card”, scientists can characterize the image identification problem in the following way: Imagine that the experiment begins with a large set of photographs chosen at random; a person secretly selects just one of these and look at it while the examiner measures his/her brain activity. Given the set of possible photographs and the measurements of a person's brain activity, the decoder attempts to identify which specific photograph he/she saw. Regarding the accuracy of the decoder, Gallant said that the decoder correctly identifies the image about 90% of the time if given a set of 120 images. “When the set grows to 1,000 images the decoder correctly identifies the image about 80% of the time.” says Gallant. Meaning that the data gathered by researchers suggest that they might be able to use brain activity measurements to identify the precise image a person visualizes, about once out of every five times. The success of this decoder legalizes the computational model of the visual cortex used in this study. The researchers stated that their model is an alternative for the ones developed by the sensory neuroscience community over the last 50 years. The study also suggests that FMRI-based measurements of brain activity contain much more information regarding underlying neural processes than expected. The study raises the possibility to visualize scenes from a person's dreams or memory in the future. “There is so much information available in brain signals that may be possible to rebuild the visual contents of dreams or visual imagery.” Gallant added. Gallant stated that the experiment that they did suggests that it might one day be possible to decode dreams, but that date is still in the future. “The FMRI method we used here measures blood flow, and it is very slow. Events that happen in less than ~3 seconds can't really be measured. So it is difficult to decode any events that unfold in time. “If we could overcome the time limitation (with new technology) and build better models, one should be able to decode them, then one could record them and watch them later. When or if this will happen, no one knows.” Gallant said. Referring to possible future applications of this technology, Gallant explained that this technique could be applied to assist in diagnosis of diseases (e.g., stroke, dementia); to evaluate the impacts of therapeutic interference (drug therapy, stem cell therapy); or as the computational heart of a neural prosthesis. “It could also be used to build a brain-machine interface and for applying this technology in other fields such as detective work, court cases and trails.” says Gallant. Gallant referred to the possibility of using this technology in the legal system to be associated with many problems because of eyewitness testimony. “Witnesses don't realize that their memory is usually poor; their remembrance tends to be unfair by overruling events, inadvertent coaching, and rehearsal; and they often confabulate stories to make logical sense of events that they cannot recall well.” Gallant said. Such errors are considered to stem from several factors: weakness of original storage of information in memory; modifications that occur to stored memories over time; and faulty recall. However, the researchers have cautioned about ethical or privacy issues that might be involved in the future, when scanning techniques improve. “It is possible that decoding brain activity could have serious ethical and privacy implications downstream in, say, the 30 to 50-year time frame,” Gallant concluded. The researchers believe strongly that no one should be subjected to any form of brain-reading process unwillingly, secretly, or without complete informed consent. __
