Intelligence and variability in a simple timing task share neural substrates in the prefrontal white matter.
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.
Ullén
Fredrik
F
Neuropediatric Research Unit Q2:07, Department of Woman and Child Health, Karolinska Institutet, SE-171 77 Stockholm, Sweden. fredrik.ullen@ki.se
Forsman
Lea
L
Blom
Orjan
O
Karabanov
Anke
A
Madison
Guy
G
D000328:Adult; D001931:Brain Mapping / Q000379:methods; D003071:Cognition / Q000502:physiology; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*