London Taxi Drivers and Bus Drivers A Structural

London Taxi Drivers and Bus Drivers: A Structural MRI and Neuropsychological Analysis E. A. Maguire, K. Wollett & H. J. Spiers

Taxi VS Bus

Background • Taxi Drivers • “The Knowledge” – 2 -4 yr training – 25, 000 streets! • Bus drivers • Approx. 6 weeks of training • Drive ~12 set routes

MRI taxi drivers (Maguire et. al. 2000) • MRI shows – ↑ gray matter volume in p. hippocampus – ↓ gray matter volume in a. hippocampus • ↑ yrs driving taxi ↑ p. hippocampus & ↓ a. hippocampus!

MRI of Hippocampus (Maguire et. al. 2000)

Current Study: Is hippocampal ∆ really from spatial learning? • Driving around London requires: – – – Vigilance Attention Motor planning Execution Stress • May have impact on hippocampal gray matter? ! • Is “The Knowledge” acquired at some expense?

Enter the Bus drivers! • Taxi vs. Bus drivers – To “control” for self-motivation, driving experience & stress on gray matter volume • Taxi – Free movement • Bus – Set route

Who? • 18 Taxi drivers • 17 Bus drivers

Neuropsychological Tests • Assessed – Basic cognitive memory – Working memory – Attention – Digit span (7 +/- 2) – Stress – Recognition • London land mark test • In London (yes/no) & which landmark closer

Perceived stress scale example • • • 1. In the last month, how often have you been upset because of something that happened unexpectedly? ___0=never ___1=almost never ___2=sometimes ___3=fairly often ___4=very often 2. In the last month, how often have you felt that you were unable to control the important things in your life? ___0=never ___1=almost never ___2=sometimes ___3=fairly often ___4=very often 3. In the last month, how often have you felt nervous and "stressed"? ___0=never ___1=almost never ___2=sometimes ___3=fairly often ___4=very often 4. In the last month, how often have you felt confident about your ability to handle your personal problems? ___0=never ___1=almost never ___2=sometimes ___3=fairly often ___4=very often 5. In the last month, how often have you felt that things were going your way? ___0=never ___1=almost never ___2=sometimes ___3=fairly often ___4=very often From: http: //www. macses. ucsf. edu/Research/Psychosocial/notebook/PSS 10. html

Procedure • Tested individually – One 2 hr session – MRI & neuropsychological assessment in random order – 2 taxi drivers quit (claustrophobia in MRI)

http: //www. youtube. com/watch? v=7 g 5 UVr. Ot 2 CI

Results • Taxi drivers compared to Bus drivers – Greater gray matter volume in right/left mid-posterior hippocampi – Less volume in anterior head of right/left hippocampi • NO difference in Caudate Nucleus (learning & memory)

mp. Hippocampus Coronal Sagittal Axial

Neuropsychological Tests

Neuropsychological Tests cont.

No difference in Stress/Anxiety Not the reason for ∆ in Hippocampal size!

Taxi driving exp. on volume

Discussion • This study confirms 2000 study • “The Knowledge” comes with a price – ↓acquiring/retrieving new visuospatial info • ∆’s not due to stress

Discussion cont. • “The Knowledge” becomes sharper with time – ↑Yrs driving taxi, ↑ p. hippocampi volume – Similar with musicians, jugglers & bilinguals • Costs/Benefits? • Evolutionarily? • Beyond London?

Thank you