Neural substrates of real and imagined sensorimotor coordination.

Much debate in the behavioral literature focuses on the relative contribution of motor and perceptual processes in mediating coordinative stability. To a large degree, such debate has proceeded independently of what is going on in the brain. Here, using blood oxygen level-dependent measures of neural activation, we compare physically executed and imagined rhythmic coordination in order to better assess the relative contribution of hypothesized neuromusculoskeletal mechanisms in modulating behavioral stability. The executed tasks were to coordinate index finger to thumb opposition movements of the right hand with an auditory metronome in either a synchronized (on the beat) or syncopated (off the beat) pattern. Imagination involved the same tasks, except without physical movement. Thus, the sensory stimulus and coordination constraints were the same in both physical and imagination tasks, but the motoric requirements were not. Results showed that neural differences between executed synchronization and syncopation found in premotor cortex, supplementary motor area, basal ganglia and lateral cerebellum persist even when the coordinative patterns were only imagined. Neural indices reflecting behavioral stability were not abolished by the absence of overt movement suggesting that coordination phenomena are not exclusively rooted in purely motoric constraints. On the other hand, activity in the superior temporal gyrus was modulated by both the presence of movement and the nature of the coordination, attesting to the intimacy between perceptual and motoric processes in coordination dynamics.