Locomotor training remodels fMRI sensorimotor cortical Activations in children after cerebral hemispherectomy
ABSTRACT 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.
- SourceAvailable from: Dongfeng Huang
[Show abstract] [Hide abstract]
- "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         . "
ABSTRACT: Stroke survivors often present with abnormal gait, movement training can improve the walking performance post-stroke, and functional MRI can objectively evaluate the brain functions before and after movement training. This paper analyzes the functional MRI changes in patients with ischemic stroke after treadmill training with voluntary and passive ankle dorsiflexion. Functional MRI showed that there are some changes in some regions of patients with ischemic stroke including primary sensorimotor cortex, supplementary motor area and cingulate motor area after treadmill training. These findings suggest that treadmill training likely improves ischemic stroke patients' lower limb functions and gait performance and promotes stroke recovery by changing patients' brain plasticity; meanwhile, the novel treadmill training methods can better training effects.Neural Regeneration Research 11/2012; 7(31):2457-64. DOI:10.3969/j.issn.1673-5374.2012.31.007 · 0.23 Impact Factor
[Show abstract] [Hide abstract]
- "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 . "
ABSTRACT: Behavioural recovery in children who undergo medically required hemispherectomy showcase the remarkable ability of the cerebral cortex to adapt and reorganize following insult early in life. Case study data suggest that lesions sustained early in childhood lead to better recovery compared to those that occur later in life. In these children, it is possible that neural reorganization had begun prior to surgery but was masked by the dysfunctional hemisphere. The degree of neural reorganization has been difficult to study systematically in human infants. Here we present a 20-year culmination of data on our nonhuman primate model (Chlorocebus sabeus) of early-life hemispherectomy in which behavioral recovery is interpreted in light of plastic processes that lead to the anatomical reorganization of the early-damaged brain. The model presented here suggests that significant functional recovery occurs after the removal of one hemisphere in monkeys with no preexisting neurological dysfunctions. Human and primate studies suggest a critical role for subcortical and brainstem structures as well as corticospinal tracts in the neuroanatomical reorganization which result in the remarkable behavioral recovery following hemispherectomy. The non-human primate model presented here offers a unique opportunity for studying the behavioral and functional neuroanatomical reorganization that underlies developmental plasticity.Neural Plasticity 06/2012; 2012:852423. DOI:10.1155/2012/852423 · 3.60 Impact Factor
[Show abstract] [Hide abstract]
- "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. "
ABSTRACT: It has been demonstrated that automated locomotor training can improve walking capabilities in spinal cord-injured subjects but its effectiveness on brain damaged patients has not been well established. A possible explanation of the discordant results on the efficacy of robotic training in patients with cerebral lesions could be that these patients, besides stimulation of physiological motor patterns through passive leg movements, also need to train the cognitive aspects of motor control. Indeed, another way to stimulate cerebral motor areas in paretic patients is to use the cognitive function of motor imagery. A promising possibility is thus to combine sensorimotor training with the use of motor imagery. The aim of this paper is to assess changes in brain activations after a combined sensorimotor and cognitive training for gait rehabilitation. The protocol consisted of the integrated use of a robotic gait orthosis prototype with locomotor imagery tasks. Assessment was conducted on two patients with chronic traumatic brain injury and major gait impairments, using functional magnetic resonance imaging. Physiatric functional scales were used to assess clinical outcomes. Results showed greater activation post-training in the sensorimotor and supplementary motor cortices, as well as enhanced functional connectivity within the motor network. Improvements in balance and, to a lesser extent, in gait outcomes were also found.Frontiers in Human Neuroscience 11/2011; 5:146. DOI:10.3389/fnhum.2011.00146 · 2.90 Impact Factor