Primary Motor and Sensory Cortex Activation during Motor Performance and Motor Imagery: A Functional Magnetic Resonance Imaging Study

Abstract

The intensity and spatial distribution of functional activation in the left precentral and postcentral gyri during actual motor performance (MP) and mental representation [motor imagery (MI)] of self-paced finger-to-thumb opposition movements of the dominant hand were investigated in fourteen right-handed volunteers by functional magnetic resonance imaging (fMRI) techniques. Significant increases in mean normalized fMRI signal intensities over values obtained during the control (visual imagery) tasks were found in a region including the anterior bank and crown of the central sulcus, the presumed site of the primary motor cortex, during both MP (mean percentage increase, 2.1%) and MI (0.8%). In the anterior portion of the precentral gyrus and the postcentral gyrus, mean functional activity levels were also increased during both conditions (MP, 1.7 and 1.2%; MI, 0.6 and 0.4%, respectively). To locate activated foci during MI, MP, or both conditions, the time course of the signal intensities of pixels lying in the precentral or postcentral gyrus was plotted against single-step or double-step waveforms, where the steps of the waveform corresponded to different tasks. Pixels significantly (r > 0.7) activated during both MP and MI were identified in each region in the majority of subjects; percentage increases in signal intensity during MI were on average 30% as great as increases during MP. The pixels activated during both MP and MI appear to represent a large fraction of the whole population activated during MP. These results support the hypothesis that MI and MP involve overlapping neural networks in perirolandic cortical areas.

Cortical activation during executed, imagined, observed, and passive wrist movements in healthy volunteers and stroke patients

“…It has been suggested that kinesthetic motor imagery involves the same neural network as motor planning (Jeannerod, 1994;Jeannerod and Frak, 1999), which in turn is thought to rely on the same motor structures as motor execution (Johnson-Frey, 2004;Munzert et al, 2009;Sharma et al, 2006). In support of this view, motor imagery shares a number of similarities with overt movement execution, such as behavioral (Decety and Jeannerod, 1995) and physiological parameters (Kranczioch et al, 2008(Kranczioch et al, , 2009, and, importantly, the functional neuroanatomical correlates (Decety, 1996;Lotze and Halsband, 2006;Porro et al, 1996;Szameitat et al, 2007aSzameitat et al, , 2007b. In line with these findings, mental practice, i.e.…”

Mental imaging of motor activity in humans

“…Porro et al were also able to determine that pixels activated during both motor performance and motor imagery represent a large fraction of the whole population of pixels activated during motor performance (note that the question of whether these pixels contain corticospinal cells cannot be answered using such methods). It remains that primary motor cortex activation reported during motor imagery amounts to only ~30% of the level observed during execution [22,23]. For an indirect confirmation of these results using quantified electroencephalography and neuromagnetic techniques, see [24][25][26].…”

“…fMRI studies, however, unambiguously demonstrate that pixels activated during contraction of a muscle (an intrinsic hand muscle, for example) are also activated during imagery of a movement involving the same muscle [22]. Porro et al [23] carefully demonstrated this point in comparing fMRI signal intensity during a control task (visual imagery) and two 'motor' tasks, motor performance and imagery of repetitive finger opposition movements. fMRI signals were increased during both motor tasks at the presumed site of the primary motor cortex, in the posterior portion of the precentral gyrus.…”

Motor imagery of hand actions: Decoding the content of motor imagery from brain activity in frontal and parietal motor areas

“…On a neural level, it has been proposed that MI is a simulation that uses the motor system as a substrate [Lange et al, 2006; Jeannerod 2001]. This has been supported by several neuroimaging studies showing that roughly the same brain areas are involved in both motor execution and MI [Decety et al, 1994; Deiber et al, 1996; Hanakawa et al, 2008; Lotze et al, 1999; Porro et al, 1996]. More precisely, this neural network is believed to be organized around the following motor and motor‐related regions: the supplementary motor area (SMA), the premotor cortex (PMC), the primary motor cortex (M1), posterior parietal regions such as the inferior (IPL) and the superior parietal lobe (SPL), the basal ganglia (BG), and the cerebellum [Guillot et al, 2008; Lotze et al, 1999; Munzert et al, 2009].…”