A tip of the tongue to the brain.

At one time or another, everyone encounters a peculiar kind of memory foul-up. You try in vain to recall, say, a name. All the while, it feels as if the name you're searching for is on the tip of your tongue but just won't spill out of your mouth.

Scientists have now identified brain areas that uniquely contribute to this experience. These regions mediate a mental struggle to wring the right memory out of conflicting knowledge that springs to mind during tip-of-the-tongue states, according to a report in the Aug. 30 NEURON.

Anat Maril of Harvard University and her colleagues used a functional magnetic resonance imaging scanner to monitor blood-flow changes in the brains of 14 adults during a general-knowledge test. Items on the test included "Iraq + capital" and "Chinatown + director." These served as memory cues for Baghdad and Roman Polanski, respectively.

Parts of the brain's outer layer, or cortex, sprang into action only when participants reported that they felt on the verge of remembering an answer they were sure they knew. Previous research indicates that one of these regions, which was activated on both sides of the brain, compares conflicting lines of information triggered during memory tasks, the researchers say. Activation in three other patches of right-brain tissue reflected efforts to visualize possible responses and to generate an acceptable final answer, the scientists theorize.