Navigation-related structural change in the hippocampi of taxi drivers

Structural MRIs of the brains of humans with extensive navigation experienc e, licensed London taxi drivers, were analyzed and compared with those of c ontrol subjects who did not drive taxis. The posterior hippocampi of taxi d rivers were significantly larger relative to those of control subjects. A m ore anterior hippocampal region was larger in control subjects than in taxi drivers. Hippocampal volume correlated with the amount of time spent as a taxi driver (positively in the posterior and negatively in the anterior hip pocampus). These data are in accordance with the idea that the posterior hi ppocampus stores a spatial representation of the environment and can expand regionally to accommodate elaboration of this representation in people wit h a high dependence on navigational skills. It seems that there is a capaci ty for local plastic change in the structure of the healthy adult human bra in in response to environmental demands.