Functional magnetic resonance imaging: An introduction to methods

Even when the events around us are random, it can be hard to resist the temptation to make predictions about upcoming events based on apparent patterns (for instance, betting on black in roulette because the previous five runs have come up black). Gregory McCarthy and colleagues now suggest that the prefrontal cortex is involved in making such moment-to-moment predictions. The authors used functional MRI to image brain activity while subjects viewed random sequences composed of two stimuli and found that prefrontal cortex was activated when a particular stimulus violated an apparent pattern. See pages 394 and 485.