Functional magnetic resonance imaging of motor, sensory, and posterior parietal cortical areas during performance of sequential typing movements

Abstract

We investigated the activation of sensory and motor areas involved in the production of typing movements using functional magnetic resonance imaging (fMRI). Eleven experienced typists performed tasks, in which the spatial and temporal requirements as well as the number of digits involved were varied. These included a simple uni-digit repetitive task, a uni-digit sequential task, a dual-digit sequential task, a multi-digit sequential task, and typing text from memory. We found that the production of simple repetitive keypresses with the index finger primarily involved the activation of contralateral primary motor cortex (M1), although a small activation of the supplementary motor area (SMA) and other regions was sometimes observed as well. The sequencing of keypresses involved bilateral M1 and a stronger activation of the SMA and to a lesser extent the premotor area, cingulate gyrus, caudate, and lentiform nuclei. However, the activation of these areas did not exclusively depend on the complexity of the movements, since they were often activated during more simple movements, such as alternating two keypresses repeatedly. Somatosensory and parietal regions were also found to be activated during typing sequences. The activation of parietal areas did not exclusively depend on the spatial requirements of the task, since similar activation was observed during movements within intra-personal space (finger-thumb opposition) and may instead be related to the temporal requirements of the task. Our findings suggest that the assembly of well-learned, goal-directed finger movement sequences involves the SMA and other secondary motor areas as well as somatosensory and parietal areas.

A Blueprint for Target Motion: fMRI Reveals Perceived Sequential Complexity to Modulate Premotor Cortex

“…Most interestingly for us, all involved brain areas, but particularly premotor areas, have been reported also to underlie the planning and production of motor sequences that follow an external sequential target stimulus, as particularly evident from imaging studies using the serial reaction task paradigm (Gordon et al, 1995;Grafton et al, 1995;Hazeltine et al, 1997;Hikosaka et al, 1998Hikosaka et al, , 1996Honda et al, 1998;Sadato et al, 1996;Sakai et al, 1998;Toni et al, 1998). As expected, the present outcome indicates that an attentively observed sequential signal can be a stimulus sufficient to elicit activations within a brain network closely related to that one that participates in sequential motor behavior.…”

Experience-dependent changes in cerebellar contributions to motor sequence learning

“…Further, after extensive training of monkeys on motor sequence tasks, neurons in the vicinity of SMA come to represent those sequences (30). The results of imaging studies comparing tasks that are well trained to those that are not also support the idea that SMA contributes to the representation of well-learned skilled movements (31,32). Finally, lesions of SMA have been reported to impair performance on motor sequence learning tasks (33).…”

Multivariate Granger causality analysis of fMRI data

“…The fact that neither C in nor C out dominates each other for the cerebellum and parietal areas points to the existence of bidirectional connections between these ROIs and the rest of the network and hence the As the motor task progresses into the middle temporal window, regions that guide motor performance-the cerebellum, SMA, and premotor cortex-become more prominent as indicated by their elevated clustering coefficients as compared to those in the first window. These regions are collectively responsible for timing motor responses, response preparation, and sequencing responses [Deiber et al, 1991;Gordon et al, 1998;Ivry et al 1989;Passingham, 1988;Tanji, 1996]. Although S1 is the major node in the first window, the cerebellum becomes the major node in the middle window.…”