Neuromagnetic biomarkers of visuocortical development in healthy children

Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45220, USA.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology (Impact Factor: 3.1). 09/2010; 121(9):1555-62. DOI: 10.1016/j.clinph.2010.03.029
Source: PubMed


The objective of the present study was to investigate noninvasive biomarkers for visuocortical development in healthy children.
Sixty healthy children and 20 adults were studied with a whole-head magnetoencephalography (MEG) system. The adults were included to find out when the markers stabilize. Visual evoked magnetic fields (VEFs) were evoked with full-field pattern-reversal checks.
Three response peaks were identified at 77+/-8 ms (M75), 111+/-9 ms (M100) and 150+/-11 ms (M145) for children. The latency of M75 and M100 decreased with age (p<0.01). The amplitude ratio of M100/M75 increased significantly with age (p<0.001). The differences of MEG source images between the left and right occipital cortices for M75 and M145 increased significantly with age (r=0.47 and 0.46, respectively, p<0.01).
The latency of M75 and M100 and the amplitude ratio of M100/M75 are robust biomarkers for the development of visual function in children.
The development of visual function in childhood is noninvasively measurable. The results lay a foundation for quantitative identification of developmental delay and/or abnormalities of visual function in children with brain disorders.

Download full-text


Available from: Jing Xiang, Sep 29, 2015
16 Reads
  • Source
    • "Of note, the study of high-frequency brain signals may shed light on some of the fundamental mechanisms of neuronal functions and brain disorders. Numerous challenges exist in the study of high-frequency brain signals with magnetoencephalography (MEG) and electroencephalography (EEG) (Xiang et al., 2004, 2010, 2013; Dalal et al., 2008; Papadelis et al., 2009; Chen et al., 2010; Gotman, 2010; Gummadavelli et al., 2013). First, the size of high sampling rate data can be over 12 terabytes (TB) (Blanco et al., 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies have revealed the importance of high-frequency brain signals (>70 Hz). One challenge of high-frequency signal analysis is that the size of time-frequency representation of high-frequency brain signals could be larger than 1 terabytes (TB), which is beyond the upper limits of a typical computer workstation's memory (<196 GB). The aim of the present study is to develop a new method to provide greater sensitivity in detecting high-frequency magnetoencephalography (MEG) signals in a single automated and versatile interface, rather than the more traditional, time-intensive visual inspection methods, which may take up to several days. To address the aim, we developed a new method, accumulated source imaging, defined as the volumetric summation of source activity over a period of time. This method analyzes signals in both low- (1~70 Hz) and high-frequency (70~200 Hz) ranges at source levels. To extract meaningful information from MEG signals at sensor space, the signals were decomposed to channel-cross-channel matrix (CxC) representing the spatiotemporal patterns of every possible sensor-pair. A new algorithm was developed and tested by calculating the optimal CxC and source location-orientation weights for volumetric source imaging, thereby minimizing multi-source interference and reducing computational cost. The new method was implemented in C/C++ and tested with MEG data recorded from clinical epilepsy patients. The results of experimental data demonstrated that accumulated source imaging could effectively summarize and visualize MEG recordings within 12.7 h by using approximately 10 GB of computer memory. In contrast to the conventional method of visually identifying multi-frequency epileptic activities that traditionally took 2–3 days and used 1–2 TB storage, the new approach can quantify epileptic abnormalities in both low- and high-frequency ranges at source levels, using much less time and computer memory.
    Frontiers in Neuroinformatics 05/2014; 8. DOI:10.3389/fninf.2014.00057 · 3.26 Impact Factor
  • Source
    • "Magnetoencephalography (MEG) has become an important tool to investigate cortical activity related to sensory or cognitive processing in children of various ages (e.g., Kimura et al., 2004; Chen et al., 2010; Ciesielski et al., 2010; Gummadavelli et al., 2013). Until recently, pediatric MEG has been predominantly performed with systems designed for adult heads. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A child-customized magnetoencephalography system was used to investigate somatosensory evoked field (SEF) in 3- to 4-year-old children. Three stimulus conditions were used in which the children received tactile-only stimulation to their left index finger or visuotactile stimulation. In the two visuotactile conditions, the children received tactile stimulation to their finger while they watched a video of tactile stimulation applied either to someone else's finger (the finger-touch condition) or to someone else's toe (the toe-touch condition). The latencies and source strengths of equivalent current dipoles (ECDs) over contralateral (right) somatosensory cortex were analyzed. In the preschoolers who provided valid ECDs, the stimulus conditions induced an early-latency ECD occurring between 60 and 68 ms mainly with an anterior direction. We further identified a middle-latency ECD between 97 and 104 ms, which predominantly had a posterior direction. Finally, initial evidence was found for a late-latency ECD at about 139-151 ms again more often with an anterior direction. Differences were found in the source strengths of the middle-latency ECDs among the stimulus conditions. For the paired comparisons that could be formed, ECD source strength was more pronounced in the finger-touch condition than in the tactile-only and the toe-touch conditions. Although more research is necessary to expand the data set, this suggests that visual information modulated preschool SEF. The finding that ECD source strength was higher when seen and felt touch occurred to the same body part, as compared to a different body part, might further indicate that connectivity between visual and tactile information is indexed in preschool somatosensory cortical activity, already in a somatotopic way.
    Frontiers in Human Neuroscience 03/2014; 8:170. DOI:10.3389/fnhum.2014.00170 · 2.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High-frequency oscillations in the brain open a new window for studies of language development in humans. The objective of this study is to determine the spatiotemporal and frequency signatures of word processing in healthy children. Sixty healthy children aged 6-17 years were studied with a whole-cortex magnetoencephalography (MEG) system using a word recognition paradigm optimized for children. The temporal signature of neuromagnetic activation was measured using averaged waveforms. The spatial and frequency signatures of neuromagnetic activation were assessed with wavelet-based beamformer analyses. The results of waveform analyses showed that the latencies of the first and third neuromagnetic responses changed with age (p<0.01). The source imaging data revealed a clear lateralization of source activation in the 70-120Hz range in children within the age range of 6 to 13 years of age (p<0.01). Males and females demonstrated different developmental trajectories over the age range of 9 to 13 years of age (p<0.01). These findings suggest that left-hemisphere language processing emerges from early bilateral brain areas with gender optimal neural networks. The neuromagnetic signatures of language development in healthy children may be used as references for future identification of aberrant language function in children with various disorders.
    Brain research 01/2013; 1498. DOI:10.1016/j.brainres.2013.01.001 · 2.84 Impact Factor
Show more