Parieto-frontal Networks for Clock Drawing Revealed with Fmri

We studied the neural substrates of clock drawing using functional magnetic resonance imaging in 18 right-handed volunteers. In the test condition, subjects were required to draw the hands of a clock corresponded to the time presented acoustically. In the control task, they drew horizontal and vertical lines after reciting silently the numerals of three figures presented acoustically. In group analyses, comparison between the test and control condition revealed brain areas related to clock drawing; bilateral posterior parietal cortices with a right side dominance, bilateral dorsal premotor areas, the left pre-supplementary motor area, the left ventral prefrontal cortex, the left precentral gyrus, and bilateral cerebellum. In particular, the posterior parietal cortex and the dorsal premotor area, which were strongly activated in all 18 subjects examined in individual analyses, appear to be the main constituent of the parieto-frontal cortical networks for clock drawing.