Functional magnetic resonance imaging of complex human movements

Abstract

Functional magnetic resonance imaging (FMRI) is a new, noninvasive imaging tool thought to measure changes related to regional cerebral blood flow (rCBF). Previous FMRI studies have demonstrated functional changes within the primary cerebral cortex in response to simple activation tasks, but it is unknown whether FMRI can also detect changes within the nonprimary cortex in response to complex mental activities. We therefore scanned six right-handed healthy subjects while they performed self-paced simple and complex finger movements with the right and left hands. Some subjects also performed the tasks at a fixed rate (2 Hz) or imagined performing the complex task. Functional changes occurred (1) in the contralateral primary motor cortex during simple, self-paced movements; (2) in the contralateral (and occasionally ipsilateral) primary motor cortex, the supplementary motor area (SMA), the premotor cortex of both hemispheres, and the contralateral somatosensory cortex during complex, self-paced movements; (3) with less intensity during paced movements, presumably due to the slower movement rates associated with the paced (relative to self-paced) condition; and (4) in the SMA and, to a lesser degree, the premotor cortex during imagined complex movements. These preliminary results are consistent with hierarchical models of voluntary motor control.

An fMRI Study of the Effect of Amphetamine on Brain Activity,

“…Figure 6 shows the "group-average" activation maps for the FT task superimposed on images of "average" brain structure. The areas of activation are similar to those observed by other investigators in both fMRI (Cao et al 1993;Rao et al 1993;Schubert et al 1998) and positron emission tomography (PET) (Fink et al 1997) experiments. The ROIs defined from these images corresponded to the following regions of the Talairach atlas: contralateral (left) primary sensorimotor cortex (CPSM), ipsilateral (right) primary sensorimotor cortex (IPSM), supplemental (right and left) motor cortex (SMA), ipsilateral (right) cerebellum (ICB), contralateral (left) cerebellum (CCB), right middle frontal area (RMF), left middle frontal area (LMF), right inferior frontal cortex (RIF), left inferior frontal cortex (LIF), thalamus (THAL), and putamen (PUT).…”

“…Nevertheless, there are reasons to believe that the increase in the number of active voxels was not simply a result of increased motor activity. The normal, healthy volunteers in the present study were instructed to tap as fast as they could, which typically results in a rate of more than 2 Hz (Rao et al 1993). Although Rao et al (1996) reported that the number of activated voxels increased between tapping rates of 1 and 2 Hz, further increases in tapping rate, in the range of 2-5 Hz, did not affect the number of active voxels.…”

“…For the FT task, the subjects were asked to continually touch their finger to their thumb in a series of sequential oppositions to the thumb, in a self-paced fashion, at the fastest consistent pace that the subject could manage (Cao et al 1993;Rao et al 1993Rao et al , 1996. Only the subject's dominant right hand was tested.…”

fMRI study of bimanual coordination

“…Finally, there is the question of whether an activity is self-paced or whether an external pacing source is provided. There is considerable agreement in the literature that the SMA is involved when sequences are voluntary/self-initiated [6,21,26,32,41]. The self-initiation role can also be related to the`intentionality' aspect of motor function that is guided by the SMA, a role anticipated by Goldberg [17].…”

Electric and magnetic fields of the brain accompanying internal simulation of movement

“…Subsequent studies employed different methods (SPECT, PET, functional MRI) and various tasks of ISM. It was consistently reported that SMA is active with internal simulation of movements but MI is not active [8,9,11,26,28,30]. In addition to SMA other parts of the cortex were reported to be active with ISM although with little consistency, possibly due to differences among the tasks employed.…”