Behavior

Intrinsic Ability

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Science  17 Sep 2010:
Vol. 329, Issue 5998, pp. 1443
DOI: 10.1126/science.329.5998.1443-b

Controlled variation is the essence of experimentation, but naturally occurring variation can be an equally powerful source of evidence, especially in situations where humans are the objects of study. Establishing the link between brain and behavior, and hence identifying potentially causal pathways, has become more feasible with improvements in neuroimaging technology. Forstmann et al. demonstrate how this approach can be applied (for another instance, see Fleming et al., Science, Reports, p. 1541) by comparing the trade-off between speed and accuracy in a simple perceptual task to the size of the white-matter tracts from the cortex to the striatum and to the subthalamic nucleus, which they localized using high-resolution 7T structural MRI. People were shown a cloud of dots in which some were moving steadily to the left or the right and the rest were moving randomly. On separate trials, they were cued to emphasize either speed or accuracy in identifying the direction. The individual differences in the flexibility with which they were able to adjust their response thresholds—that is, how much information they accumulated before making a choice—correlated positively with the structural connectivity of the cortex and the striatum and not with the cortico–subthalamic nucleus tract.

Proc. Natl. Acad. Sci. U.S.A. 107, 10.1073/pnas.1004932107 (2010).

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