A good taxicab driver listens to a passenger's request and, often before hitting the gas pedal, mentally delineates the best route to the desired destination. In the teeming neural metropolis of the brain, the road to navigational recall of this kind passes through a critical checkpoint known as the right hippocampus, a new study finds.
In familiar real-world settings, where many paths may lead to a particular destination, the right hippocampus integrates memories of spatial information so that individuals can get from point A to point B, contend neuroscientist Eleanor A. Maguire of the Institute of Neurology in London and her coworkers.
"A network of brain regions may support the construction of a mental map of space, but only the right hippocampus is specifically involved in relating the elements of a route together into a framework for navigation," Maguire holds.
The researchers examined the brains of 11 London taxi drivers, all men between 38 and 52 years old. Participants' tenure as licensed London, cabbies, a status attained through strict testing, ranged from 3 to 26 years. A positron emission tomography (PET) scanner measured changes in cerebral blood flow, an indirect sign of rises or drops in neural activity.
Blood flow in the right hippocampus, which is located near the center of the brain, increased sharply when the taxi drivers described the shortest legal route between assigned starting and destination points in London, Maguire's group reports in the Sept. …