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The double edged sword of the cabbies’ hippocampi

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With all the conferences that are going on lots of us are starting to look forward to the new 2008 specifications: what are the studies like; what else have the authors done? One of the new studies in the physiological psychology module of the AS is Maguire’s research into the size of London cabbies’ hippocampus. Through the use of MRI scanners her and her team have studied the hippocampi of London cabbies to investigate if their choice of vocation has had any cognitive or physiological effect on their brain.

McGuire’s team famously discovered in 2000 that London Taxi drivers have bigger than average hippocampi, a brain structure known to be heavily involved in learning routes and spatial representations … The study found that the size of the hippocampus correlated with the length of time being a taxi driver, suggesting that driving taxis may develop and change the hippocampus. [quote]

The conclusions of this research have massive implications and this was noted when Maguire received an Ig Nobel Prize in 2003:

For her work showing that the brains of London taxi drivers were more highly developed than the brains of non-taxi drivers, Eleanor Maguire won the 2003 Ig Nobel medicine prize. Dr Maguire, senior research fellow in neuropsychology with the Wellcome Department of Cognitive Neurology, was the lead author of “Navigation-related structural change in the hippocampi of taxi drivers,” published in the Proceedings of the National Academies of Science (2000;97:4398-403). [quote]

More recently Maguire has been conducting research into the possible implications of the cabbies extended hippocampi on their other cognitive functions. At a recent Society for Neurosceince conference Maguire presented a paper where she suggests that there may be a cognitive ‘price-to-pay’ for the expert navigational abilities a cabbies large hipocampi allows them.

[Maguire et. al] found that compared with bus drivers, taxi drivers had greater gray matter volume in mid-posterior hippocampi and less volume in anterior hippocampi. Furthermore, years of navigation experience correlated with hippocampal gray matter volume only in taxi drivers, with right posterior gray matter volume increasing and anterior volume decreasing with more navigation experience. This suggests that spatial knowledge, and not stress, driving, or self-motion, is associated with the pattern of hippocampal gray matter volume in taxi drivers. We then tested for functional differences between the groups and found that the ability to acquire new visuo-spatial information was worse in taxi drivers than in bus drivers. We speculate that a complex spatial representation, which facilitates expert navigation and is associated with greater posterior hippocampal gray matter volume, might come at a cost to new spatial memories and gray matter volume in the anterior hippocampus. [quote]

While at the conference Maguire was interviewed for the NeuroPod (a podcast produced by Nature) and she comments on the findings of this new study (the MP3 file is here; the interview starts at 23:50).

Basically, the findings of the 2006 research state that even though cabbies may have a larger hippocampus it seems to come at a cost to new learning and memory; specifically to associative memory. The growth of certain parts of the hippocampus is accompanied by a decrease in the anterior hippocampus which is instrumental in memory.

This research could suggest that this ‘give-and-take’ relationship between brain structures could be seen in different areas although there is little research in this area at the moment.

As far as OCR goes it will be interesting to follow Maguire’s future research to see what else comes out from this comparative research between London cabbies and other groups of people. So it seems that although these cabbies have a depth of knowledge of London and are expert at navigating around the capital, this talent could have the consequence of memory problems or even other cognitive deficits.

Hat-tip to Mind Hacks.

Blogging on Peer-Reviewed ResearchMaguire, E.A., Woollett, K., Spiers, H.J., (2006) London Taxi Drivers and Bus Drivers: A Structural MRI and Neuropsychological Analysis. Hippocampus, 16: 1091-1101.

Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak , R.S. & Frith, C. D. (2000) Navigation-related structural changes in the hippocampi of taxi drivers. Proceedings of the National Academy of Science, USA. 97. 4398–4403

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6 Responses to “The double edged sword of the cabbies’ hippocampi”

  1. Richard October 14, 2008 at 4:36 pm #

    I suspect the give and take is nothing more than competition. If the taxi drivers were also studying other skills of various kinds over the time period for example then it’s likely that they would develop a more balanced brain structure.

    The body can’t afford to maintain unused structures, at a guess this would apply to the brain as much as to muscles.

    Whilst there’s some crossover effect in muscles, if you exclusively train just your right forearm and ignore other muscles then only that muscle will grow significantly.

    Just a random thought on my part :).

    • jual sepatu May 24, 2014 at 7:22 am #

      forget one thing.i am a psychological fan

  2. apa January 8, 2009 at 8:12 am #

    ya,brain is magic.i really wish we could totally understand it ASAP.

  3. apa January 8, 2009 at 8:17 am #

    oh,forget one thing.i am a psychological fan, recommend my psychological website: http://bbs.sciopsy.com.:)

Trackbacks/Pingbacks

  1. Dudley Jackson » Blog Archive » Psychology, Mind and Neuroscience Roundup - January 22, 2008

    […] Enlarged hippocampi in London taxi drivers have been associated with extensive navigational knowledge.  Now, the researchers who identified this association also report that this navigational knowledge comes at a cost. H/T: PsychBLOG.co.uk […]

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