Brain activation during human finger extension and flexion movements
ABSTRACT Corticospinal projections to the motor neuron pool of upper-limb extensor muscles have been reported to differ from those of the flexor muscles in humans and other primates. The influence of this difference on the central nervous system control for extension and flexion movements is unknown. Cortical activation during thumb extension and flexion movements of eight human volunteers was measured using functional magnetic resonance imaging (fMRI), which detects signal changes caused by an alteration in the local blood oxygenation level. Although the relative activity of the extensor and flexor muscles of the thumb was similar, the brain volume activated during extension was substantially larger than that during flexion. These fMRI results were confirmed by measurements of EEG-derived movement-related cortical potential. Higher brain activity during thumb extension movement may be a result of differential corticospinal, and possibly other pathway projections to the motoneuron pools of extensor and flexor muscles of upper the extremities.
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ABSTRACT: Neuroergonomics is an emerging science that is defined as the study of the human brain in relation to performance at work and in everyday settings. This paper provides a critical review of the neuroergonomic approach to evaluating physical and cognitive work, particularly in mobile settings. Neuroergonomics research employing mobile and immobile brain imaging techniques are discussed in the following areas of physical and cognitive work: (1) physical work parameters; (2) physical fatigue; (3) vigilance and mental fatigue; (4) training and neuroadaptive systems; and (5) assessment of concurrent physical and cognitive work. Finally, the integration of brain and body measurements in investigating workload and fatigue, in the context of mobile brain/body imaging ("MoBI"), is discussed.Frontiers in Human Neuroscience 01/2013; 7:889. · 2.90 Impact Factor
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ABSTRACT: We investigated finger movements in patients with hand dystonia to compare the kinematics of repetitive individual and non-individual finger oppositions. We used an optoelectronic motion analysis system to record movements in 3-D space, and recorded three 5-second trials for each task, counting how many finger oppositions subjects carried out during each trial, and measured the duration and amplitude of flexions, extensions, and pauses. During tasks, normal subjects and patients carried out finger flexions faster than extensions, and invariably they paused longer before extension than before flexion. Patients were slower and paused longer than controls during both individual and non-individual oppositions. During individual finger movements, patients were disproportionately slow during extension and pause before extension. Patients with hand dystonia perform finger movements abnormally; they are affected predominantly during individual oppositions. This finding reflects the finer cortical control needed to promote and sustain this highly fractionated type of motor output, and points toward underactivity of the primary motor cortex in dystonia. © 2004 Movement Disorder SocietyMovement Disorders 10/2004; 19(11):1351 - 1357. · 5.63 Impact Factor
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ABSTRACT: Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional magnetic resonance imaging (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.Frontiers in Aging Neuroscience 05/2014; 6:86. · 2.84 Impact Factor