Locomotor Training Remodels fMRI Sensorimotor Cortical Activations in Children After Cerebral Hemispherectomy

University of South Carolina, Columbia, South Carolina, United States
Neurorehabilitation and neural repair (Impact Factor: 3.98). 03/2007; 21(6):497-508. DOI: 10.1177/1545968307299523
Source: PubMed


This study examined whether locomotor training, which included body weight-supported treadmill therapy, improved walking and induced cortical representational adaptations using functional magnetic resonance imaging in the remaining sensorimotor network after cerebral hemispherectomy.
Hemispherectomy patients (n = 12) underwent 2 weeks of gait training for at least 30 hours each. They were tested pre- and posttraining with the Fugl-Meyer Motor Assessment, unassisted single-limb stance time, and usual and fastest walking speeds. Three patients performed voluntary ankle movements as the functional magnetic resonance imaging activation task pre- and posttraining. Control subjects included 5 healthy children tested 2 weeks apart, 2 of whom trained on the treadmill, and 2 hemispherectomy patients who received upper extremity rehabilitation and no gait therapy.
Although patients reported improvements with gait training, behavioral outcomes did not significantly change. Training was associated with increased volume and intensity of cortical activation in the primary sensorimotor (S1M1), supplementary motor, motor cingulate, and secondary somatosensory cortex for the paretic foot, along with greater overlap in the representation for each moving foot in S1M1 and the supplementary motor area of the remaining hemisphere. Control subjects showed a decrease in activation in these cortical regions after training.
Locomotor training of hemispherectomy patients improved mobility subjectively in association with functional magnetic resonance imaging evidence of cortical remodeling with ankle dorsiflexion. These findings support the notion that hemispherectomy patients may respond to rehabilitation interventions through mechanisms of activity-dependent cortical plasticity. The authors hypothesize that developmentally persistent descending ipsilateral and contralateral corticospinal tracts may allow the remaining hemisphere to maintain bilateral lower extremity motor control after surgery.

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    • "In event-related design, the hemodynamic responses are evoked by repeated presentations of single stimulus, and the average transient response is calculated. Many functional neuroimaging studies used a block design, in which activations of brain regions are obtained by subtracting signal from blocks recorded in an " off " condition, from blocks recorded in an " on " condition [8] [9] [10] [11] [36] [37] [38] [39] . "
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    • "The remaining cortex has also been shown to undergo significant reshaping in the motor and sensorimotor cortical representations [37, 68–71]. There is evidence from fMRI studies that physical training with the paretic lower limb results in cortical activation of the remaining primary sensorimotor, supplementary motor, cingulate, and secondary somatosensory cortices, suggesting an experiential or active-dependent recovery [72]. "
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    • "To this end, we submitted two clinical cases (chronic paretic patients with TBI) to our RCGR protocol and assessed their cerebral changes using functional magnetic resonance imaging (fMRI), an in vivo imaging technique which allows the mapping of active processes within the brain. fMRI has been previously used to study training-induced plasticity in stroke patients (for a review see Nelles, 2004); locomotor training-related brain changes have been recently investigated in children with cerebral lesions (de Bode et al., 2007; Phillips et al., 2007), but similar data for adult patients is still lacking. To the best of our knowledge, there are no fMRI studies assessing RGR in adult brain injured patients. "
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