High gamma oscillations of sensorimotor cortex during unilateral movement in the developing brain: a MEG study.
ABSTRACT 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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ABSTRACT: 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.Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 04/2014; DOI:10.1016/j.clinph.2014.03.033 · 2.98 Impact Factor
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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 · 2.06 Impact Factor
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ABSTRACT: Synchronization of neural activity is considered essential for information processing in the nervous system. Both local and inter-regional synchronization are omnipresent in different frequency regimes and relate to a variety of behavioral and cognitive functions. Over the years, many studies have sought to elucidate the question how alpha/mu, beta, and gamma synchronization contribute to motor control. Here, we review these studies with the purpose to delineate what they have added to our understanding of the neural control of movement. We highlight important findings regarding oscillations in primary motor cortex, synchronization between cortex and spinal cord, synchronization between cortical regions, as well as abnormal synchronization patterns in a selection of motor dysfunctions. The interpretation of synchronization patterns benefits from combining results of invasive and non-invasive recordings, different data analysis tools, and modeling work. Importantly, although synchronization is deemed to play a vital role, it is not the only mechanism for neural communication. Spike timing and rate coding act together during motor control and should therefore both be accounted for when interpreting movement-related activity.Frontiers in Human Neuroscience 09/2012; 6:252. DOI:10.3389/fnhum.2012.00252 · 2.90 Impact Factor