Brain activation pattern according to exercise complexity: a functional MRI study.
ABSTRACT The aim of this study was to compare the areas of brain activation between complex and simple exercises in a unimanual hand and to assess the possibility of an exercise task for paretic hands following stroke. The subjects included 11 healthy right-handed volunteers. The complex exercise was a wooden ball rotation task with the unimanual hand and the simple exercise was a hand grasp task performed during a functional MRI scan. Stronger activation of the left primary sensorimotor cortex, the left premotor area, and the ipsilateral cerebellum emerged when the complex movement was performed. Ipsilateral activity was located in the primary sensory cortex and premotor area, and contralateral activity was shown in the left cerebellum. These results suggest that a unimanual ball rotation task may be appropriate for rehabilitation of a movable paretic hand in an early stage of stroke recovery, which should provide motor and sensory input using external stimuli, while the simple motor task may appropriate in a compensatory stage, and should inhibit the ipsilateral activity due to maladaptive plasticity.
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ABSTRACT: Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function (i.e., primary motor cortex, premotor area, posterior parietal cortex) showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.Neural Regeneration Research 03/2013; 8(7):639-46. · 0.23 Impact Factor
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ABSTRACT: Fast cyclic movements and discrete motor acts are controlled differently, presumably because fast cyclic tasks are more automated, thereby depending on different circuits. If fast cyclic movements are made less predictable (e.g., by mixing frequencies), one would predict that their control will be less automated, requiring increased activity in motor cortical areas. The present functional near-infrared spectroscopy (fNIRS) study investigated whether switching between frequencies increases the motor cortex activity compared to movements at single rates. Therefore, hand tapping at mixed frequencies ("mixed") was compared with hand tapping at 0.4 ("low frequency"), 0.8 ("mid-frequency"), and 1.4 Hz ("high frequency"). Oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) concentration changes were studied in eleven healthy subjects with eight-channel fNIRS covering the hand motor cortex. Repeated-measures ANOVAs revealed significant main effects for the type of task in HbO and HbR. Post hoc analysis showed a larger HbO increase and HbR decrease for the mixed task compared to the low- and high-frequency conditions. In addition, the mid-frequency condition revealed a smaller HbR decrease compared to the mixed task. Single frequency data indicated the existence of separate motor control systems for low- and high-frequency movements. The increased activity for the mixed task is suggested to be the result of the recruitment of a voluntary command motor system instead of automated systems.Experimental Brain Research 09/2013; · 2.17 Impact Factor
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ABSTRACT: It is well-known that physical exercise can affect cognition and the frontal lobe is an important structure involved in motor function and cognition. Furthermore, many functional neuroimaging studies have demonstrated that cortical activation patterns of hand and leg movements differ. However, no study has been undertaken to identify differences between the frontal activation patterns generated by hand and leg movements. In the present study, the frontal activation patterns associated with finger and toe movements, as visualized by functional MRI, were investigated and compared. Twelve healthy volunteers were recruited. Functional MRI was performed using a 1.5-T Philips Gyroscan Intera. Flexion-extension movements of fingers or toes were performed in one extremity. Regions of interest (ROIs) were set at the primary sensory-motor cortex (SM1: Brodmann area [BA] 1, 2, 3, 4), the premotor area (PMA: BA 6), and the prefrontal cortex (PFC: BA 8, 9, 10, 11, 46). In SM1, finger movements (10809) induced more activation than toe movements (5349). On the other hand, in the PMA and PFC, toe movements (PMA: 4201, PFC: 921) induced more activation than finger movements (PMA: 2887, PFC: 912) respectively. In the analysis of relative voxel counts in the PMA and PFC versus the SM1, toe movements generated more activation in the PMA and PFC than finger movements. The PMA and PFC were more activated by toe than finger movements, although the SM1 was more activated by finger movements.Neuroscience Letters 11/2012; · 2.06 Impact Factor