How many times have you forgotten where you left your wallet or let your dog go astray? How about your child? Well, aside from the heightened sense of panic, a new study reveals your brain mobilizes certain areas, even switching other regions off, in order to shift all attention to recovering the lost.

"Our results show that our brains are much more dynamic than previously thought, rapidly reallocating resources based on behavioral demands, and optimizing our performance by increasing the precision with which we can perform relevant tasks," said Tolga Cukur, lead author and postdoctoral researcher in neuroscience at the University of California, Berkeley.

Using functional magnetic resonance imaging, fMRI, which tracks brain activity through the changes in blood flow and oxygen levels, researchers uncovered regions of the brain that activate and mobilize to retrieve lost or misplaced items.

"As you plan your day at work, for example, more of the brain is devoted to processing time, tasks, goals and rewards, and as you search for your cat, more of the brain becomes involved in recognition of animals," Cukur said.

This not only explains why an individual is able to adjust their attention to challenging tasks, but also why people find it difficult to focus on one item at a time — a struggle particularly accute for those diagnosed with attention deficit disorders like ADHD. According to the American Psychiatric Association, between three and seven percent of all school-aged children have ADHD, although the numbers are believed to be higher due to recent changes in diagnostic tools.

In this study, activity was measured across various regions of the brain as participants were told to find individuals or vehicles in movie scenes and press a button whenever someone or the vehicle appeared. The scientists recorded almost 50,000 sites around the cortex, which is the outermost layer of the brain. More regions of the cortex involved in recognizing plants and inanimate objects like buildings switched to look for people or vehicles, depending on the task.

"These changes occur across many brain regions, not only those devoted to vision. In fact, the largest changes are seen in the prefrontal cortex, which is usually thought to be involved in abstract thought, long-term planning and other complex mental tasks," Cukur said.

The investigators also created an interactive online brain viewer that illustrates the parts of the cortex activated during a search.

The study appears in the April 21 edition of the journal Nature Neuroscience.