High Gamma Oscillations of Sensorimotor Cortex During Unilateral Movement in the Developing Brain: a MEG Study
Department of Neurology, MLC 2015, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.Brain Topography (Impact Factor: 3.47). 01/2011; 23(4):375-84. DOI: 10.1007/s10548-010-0151-0
Recent studies in adults have found consistent contralateral high gamma activities in the sensorimotor cortex during unilateral finger movement. However, no study has reported on this same phenomenon in children. We hypothesized that contralateral high gamma activities also exist in children during unilateral finger movement. Sixty normal children (6-17 years old) were studied with a 275-channel MEG system combined with synthetic aperture magnetometry (SAM). Sixty participants displayed consistently contralateral event-related synchronization (C-ERS) within high gamma band (65-150 Hz) in the primary motor cortices (M1) of both hemispheres. Interestingly, nineteen younger children displayed ipsilateral event-related synchronization (I-ERS) within the high gamma band (65-150 Hz) just during their left finger movement. Both I-ERS and C-ERS were localized in M1. The incidence of I-ERS showed a significant decrease with age. Males had significantly higher odds of having ipsilateral activity compared to females. Noteworthy, high gamma C-ERS appeared consistently, while high gamma I-ERS changed with age. The asymmetrical patterns of neuromagnetic activities in the children's brain might represent the maturational lateralization and/or specialization of motor function. In conclusion, the present results have demonstrated that contralateral high-gamma neuromagnetic activities are potential biomarkers for the accurate localization of the primary motor cortex in children. In addition, the interesting finding of the ipsilateral high-gamma neuromagnetic activities opens a new window for us to understand the developmental changes of the hemispherical functional lateralization in the motor system.
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- "s ( ERD ) that begin up to 1 . 5 s prior to movement onset and transitions to beta synchronization ( ERS ) within 1 / 2 s of movement offset [ Cassim et al . , 2001 ; Jurkiewicz et al . , 2006 ] . Previous MEG studies have reported beta ERD and ERS in older children and adolescents with marked decreases in younger children [ Gaetz et al . , 2010 ; Huo et al . , 2011 ; Wilson et al . , 2010 ] . In the current study , we observed both mu and beta ERD in the children but with a later latency , around 200 – 250 ms prior to move - ment onset . This later ERD onset might be attributed to our use of cued movements instead of the self - paced movement para - digm employed in the previous studies ( the 3 – "
ABSTRACT: We examined sensorimotor brain activity associated with voluntary movements in preschool children using a customized pediatric MEG system. A videogame-like task was used to generate self-initiated right or left index finger movements in seventeen healthy right-handed subjects (8 female, ages 3.2 to 4.8 years). We successfully identified spatiotemporal patterns of movement-related brain activity in 15/17 children using beamformer source analysis and surrogate MRI spatial normalization. Readiness fields in the contralateral sensorimotor cortex began approximately 0.5 s prior to movement onset (motor field, MF), followed by transient movement-evoked fields (MEFs), similar to that observed during self-paced movements in adults, but slightly delayed and with inverted source polarities. We also observed modulation of mu (8-12 Hz) and beta (15-30 Hz) oscillations in sensorimotor cortex with movement, but with different timing and a stronger frequency band coupling compared to that observed in adults. Adult-like high-frequency (70-80 Hz) gamma bursts were detected at movement onset. All children showed activation of the right superior temporal gyrus that was independent of the side of movement, a response that has not been reported in adults. These results provide new insights into the development of movement-related brain function, for an age group in which no previous data exist. The results show that children under 5 years of age have markedly different patterns of movement-related brain activity in comparison to older children and adults, and indicate that significant maturational changes occur in the sensorimotor system between the preschool years and later childhood.Human Brain Mapping 09/2014; DOI:10.1002/hbm.22518 · 5.97 Impact Factor
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- "The stimulation presentation and response recording were accomplished with BrainX software, which was based on DirectX (Microsoft Corporation, Redmond, WA, USA) (Huo et al., 2011; Wang et al., 2010; Xiang et al., 2001, 2013). The entire procedure took about 15 min. "
ABSTRACT: Objective: The objective of this study was to investigate functional abnormalities of the brain in females with migraine using magnetoencephalography (MEG) and a finger-tapping task. Methods: Twenty-nine female patients with migraine (aged 16-40. years) and age- and gender-matched healthy controls were studied with an MEG system at a sampling rate of 6000. Hz. MEG recordings were performed during an attack in migraineurs with and without aura. Neuromagnetic brain activation was elicited by a finger-tapping task. The latency and amplitude of neuromagnetic responses were analyzed with averaged waveforms in the frequency range of 5-100. Hz. The Morlet wavelet and beamformers were used to analyze the spectral and spatial signatures of MEG data from subjects in two frequency ranges of 5-100 and 100-1000. Hz. Results: The latency of motor-evoked magnetic fields evoked by finger movement was significantly prolonged in migraineurs as compared with controls. Neuromagnetic spectral power in the motor cortex in migraineurs was significantly elevated. There were significantly higher odds of activation in 5-30, 100-300 and 500-700. Hz frequency ranges in the ipsilateral primary motor cortices and the supplementary motor area in migraineurs as compared with controls. Conclusions: Neuromagnetic signal abnormalities in this study suggest cortical hyperexcitability in females with migraine during migraine attack, which could be measured and analyzed with MEG signal in a frequency range of 5-1000. Hz. Significance: These findings may help to identify neurophysiological biomarkers for studying mechanisms of migraine, and may facilitate to develop new therapeutic strategies for migraine by alterations in cortical excitability.Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 04/2014; 126(1). DOI:10.1016/j.clinph.2014.03.033 · 3.10 Impact Factor
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- "MEG waveforms were transformed to spectrograms, the time–frequency representations of MEG data, using Morlet continuous wavelet transform (CWT)  . Morlet wavelet can be described by the following equation: "
ABSTRACT: This study aimed to use ictal high-frequency oscillations (HFOs) ranging from 80Hz to 500Hz to locate seizure onset zones in childhood absence epilepsy (CAE) using non-invasive magnetoencephalography (MEG). Ten drug-naïve children with CAE were studied using a 275-channel MEG system. MEG data were digitized at a sampling rate of 6000Hz. HFO spectral power in real-time spectrograms was assessed using Morlet continuous wavelet transform. Magnetic sources were volumetrically localized through dynamic magnetic source imaging with a slide window. HFOs were identified in all patients. The total time of fast ripples (250-500Hz) was greater than that of ripples (80-250Hz) during absence seizures. The rate of fast ripples was associated with seizure frequency. HFO duration was significantly longer when co-occurring with spikes than when occurring independently, and the maximum frequency of HFOs co-occurring with spikes was higher than that of HFOs occurring independently. HFOs were predominantly localized in the medial prefrontal cortex (MPFC), whereas spikes were widespread to a variety of regions during the absence seizures. Compared with spikes, HFOs appeared to be more focal. The findings indicate that HFOs in the MPFC have a primary function in initializing epileptic activity in CAE.Neuroscience Letters 02/2014; 566. DOI:10.1016/j.neulet.2014.02.038 · 2.03 Impact Factor
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