The researchers are now trying to collect additional information from these brief brain activity patterns. “Sometimes, we would see a second bump in Broca’s area,” says Posse. “Subjects then told us they had thought of a second word.”
Eventually, the researchers hope to be able deduce even more complicated characteristics–such as the type of word the person generated, whether the word made them feel happy or angry, and, ultimately, more complex thoughts. “If you can see activity generated by a single word, maybe you can also see activity from a longer sequence of thoughts, then complex brain processes,” says Posse. “The idea is to be able to decompose the stream of thought processes into individual thoughts.”
Brain-imaging experts say a technique that reliably measured single thoughts could open up a new world of experiments. “If we can succeed in measuring data from a single trial, it gives us a more powerful method than what’s been available,” says deCharms. “You could monitor performance in a task, like surgery or flying a plane, if you wanted to understand how performance changes second by second.”
And this single-thought method could be used to study the learning process itself, which “happens very quickly,” says deCharms. “You can only have a first impression once.” To study a specific learning process, scientists would need to measure the difference in brain activity between the first time someone performs a new skill and the second or third. “If you have to average over 20 trials, you lose a lot of insight,” says deCharms.
Single-trial brain-imaging techniques could also be useful in the clinic. Currently, fMRI is rarely used for diagnostic or therapeutic purposes because it is difficult to gather reliable data from an individual brain image. But as fMRI techniques such as Posse’s allow more-sensitive imaging, doctors will be better able to make medical decisions from individual brain scans. In addition, says Bandettini, the ability to generate reliable images in shorter amounts of time will make the process easier for both doctors and patients.