The Journal of Neuroscience, April 16, 2008, 28(16):4238-4243; doi:10.1523/JNEUROSCI.0825-08.2008
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Behavioral/Systems/Cognitive
Intelligence and Variability in a Simple Timing Task Share Neural Substrates in the Prefrontal White Matter
Fredrik Ullén,1
Lea Forsman,1
Örjan Blom,1
Anke Karabanov,1 and
Guy Madison2
1Department of Woman and Child Health, Karolinska Institutet, SE-171 77 Stockholm, Sweden, and 2Department of Psychology, Umeå University, SE-901 87 Umeå, Sweden
Correspondence should be addressed to Fredrik Ullén, Neuropediatric Research Unit Q2:07, Department of Woman and Child Health, Karolinska Institutet, SE-171 76 Stockholm, Sweden. Email: fredrik.ullen{at}ki.se
General intelligence is correlated with the mean and variability of reaction time in elementary cognitive tasks, as well as with performance on temporal judgment and discrimination tasks. This suggests a link between the temporal accuracy of neural activity and intelligence. However, it has remained unclear whether this link reflects top-down mechanisms such as attentional control and cognitive strategies or basic neural properties that influence both abilities. Here, we investigated whether millisecond variability in a simple, automatic timing task, isochronous tapping, correlates with intellectual performance and, using voxel-based morphometry, whether these two tasks share neuroanatomical substrates. Stability of tapping and intelligence were correlated and related to regional volume in overlapping right prefrontal white matter regions. These results suggest a bottom-up explanation of the link between temporal stability and intellectual performance, in which more extensive prefrontal connectivity underlies individual differences in both variables.
Key words: cognition; morphometry; motor control; prefrontal; temporal; white matter
Received Dec. 28, 2007;
revised March 11, 2008;
accepted March 12, 2008.
Correspondence should be addressed to Fredrik Ullén, Neuropediatric Research Unit Q2:07, Department of Woman and Child Health, Karolinska Institutet, SE-171 76 Stockholm, Sweden. Email: fredrik.ullen{at}ki.se