Most of us draw on our visual recognition and short-term memory abilities many times a day and with relatively little fanfare, but these seemingly mundane activities have rather complex underpinnings within our brains. The tasks involve different, non-adjacent brain regions: short-term memory formation occurs in the lateral prefrontal cortex (PFC), and visual information processing primarily takes place in the occipital lobe, in the back part of the brain's cerebral cortex. It is believed that these brain regions must interact during tasks requiring the use of short-term memories for visual recognition, but the nature and mechanism of their interaction is not well understood.

Stefanie Liebe and Gregor Rainer (Max Planck Institute for Biological Cybernetics, Tuebingen, Germany) led a study to investigate the potential interaction between the brain areas. They examined neural communication between the PFC and visual area V4 during short-term memory formation and recall in two adult male macaques (Macaca mulatta) performing a visual recognition task. The monkeys were shown a sample image from a set including birds, flowers, butterflies and monkeys in their natural surroundings. Then, after a brief delay, they were shown a test image that was either identical to or different from the sample. The monkeys were given juice when they correctly indicated whether or not the test image matched the sample.

Liebe and Rainer's group found that electrical oscillations in the PFC and V4 became synchronized during memory formation, particularly in a range of frequencies (3–9 Hz) called the theta band (Nat. Neurosci. doi:10.1038/nn.3038; published online 29 January 2012). “It is as if you have two revolving doors in each of the two areas. During working memory, they get in sync, thereby allowing information to pass through them much more efficiently than if they were out of sync,” explained Liebe in a press release.

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Stronger synchronization between the two regions resulted in better recall performance in the macaques, a finding that demonstrates how changes in the electrical activity of the brain can contribute directly to behavior. The researchers conclude that theta-band synchronization may enable short-term visual memory by coordinating communication between the distant PFC and V4 regions.

Interaction between distant regions of the brain is crucial in many cognitive functions in addition to visual recognition. More research is needed to understand how these interactions are established and maintained, as well as how they participate in the transmission of information.