Subjects viewed a random series of simple shapes presented one at a time in rapid sequence. Even though the shapes were presented randomly, short term patterns arose by chance within the sequence. Huettel, Mack, and McCarthy (2002) found that regions within the prefrontal cortex, as well as related subcortical brain regions, showed transient increases in activity to events that violated these short term patterns. Importantly, this effect was found for violations of both repeating and alternating patterns, confirming that pattern recognition and not sensory or motor habituation was responsible. These results were published as the cover article in the May 2002 issue of Nature Neuroscience.
Citation: Huettel SA, Mack PB, McCarthy G. Perceiving patterns in random series: dynamic processing of sequence in prefrontal cortex. Nat Neurosci. 2002 May;5(5):485-90. doi: 10.1038/nn841. PMID: 11941373.