Measurement of brain function in pre-school children using a custom sized whole-head MEG sensor array

Johnson, Blake W.; Crain, Stephen; Thornton, Rosalind; Tesan, Graciela; Reid, Melanie

doi:10.1016/j.clinph.2009.10.017

Cited by 75 publications

(53 citation statements)

References 19 publications

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“…Both systems were housed in the same magnetically shielded room (MSR, Fujihara Co. Ltd., Tokyo, Japan). Detailed descriptions and specification of this device are available in Johnson et al (2010) and He et al (2014).…”

Section: Data Acquisitionmentioning

confidence: 99%

“…The adult system (Model PQ1160R-N2, KIT, Kanazawa, Japan) consisted of 160 coaxial first-order gradiometers with a 50 mm baseline (Kado et al, 1999). The child system (Model PQ1064R-N2m, KIT, Kanazawa, Japan) consisted of 64 firstorder axial gradiometers with a 50 mm baseline (Johnson et al, 2010). Both systems were housed in the same magnetically shielded room (MSR, Fujihara Co. Ltd., Tokyo, Japan).…”

Section: Data Acquisitionmentioning

confidence: 99%

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Face processing in the brains of pre-school aged children measured with MEG

Brock

Johnson

2015

NeuroImage

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There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions.

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Section: Data Acquisitionmentioning

confidence: 99%

Section: Data Acquisitionmentioning

confidence: 99%

Face processing in the brains of pre-school aged children measured with MEG

Brock

Johnson

2015

NeuroImage

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“…This is discussed more extensively in a later section. There have been attempts to develop smaller custom sized helmets [24,54], but these are not commonly available. However, the hope is that as more groups pursue developmental studies and highlight the need for new pediatric developments, this will spur commercial developments and industry to invest in developing hardware that is child-appropriate.…”

Section: Introductionmentioning

confidence: 99%

Practical Aspects of Running Developmental Studies in the MEG

Pang

2011

Brain Topogr

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Developmental neuroimaging studies offer a unique opportunity to gain insight into the underpinnings of various cognitive functions by examining age-related changes in brain structure and function. There is an increasing body of neuroimaging literature discussing issues related to testing children in developmental studies [8]. These deal with fMRI developmental studies and discuss methods [31], data interpretation [40], and theoretical approaches [26]. There has not yet been an equivalent discussion for MEG developmental studies. This paper will address issues specific to data acquisition, analysis, and interpretation for MEG developmental studies.

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“…Child MEG system: Data acquisition is done using a whole-head child MEG system (KIT, Kanazawa, Japan) [2]. Data is acquired continuously at a sample rate of 1000Hz, with an online band pass filter between 0.03 Hz and 200Hz.…”

Section: Equipment Used During Data Acquisition and Experimental Taskmentioning

confidence: 99%

“…The KIT-Macquarie Brain Research Laboratory at Macquarie University uses a MEG system custom sized to fit the heads of pre-school children. This child system has 64 first-order axial gradiometers with a 50 mm baseline [2] and is contained inside a magnetically-shielded room (MSR) together with a conventional adult-sized MEG system [3,4]. There are three main advantages of the customized helmet dewar for studying children.…”

Section: Introductionmentioning

confidence: 99%

Measurement Of Neuromagnetic Brain Function In Pre-school Children With Custom Sized MEG

Tesan

Johnson

Reid

et al. 2010

JoVE

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Magnetoencephalography is a technique that detects magnetic fields associated with cortical activity [1]. The electrophysiological activity of the brain generates electric fields -that can be recorded using electroencephalography (EEG)-and their concomitant magnetic fields -detected by MEG. MEG signals are detected by specialized sensors known as superconducting quantum interference devices (SQUIDs). Superconducting sensors require cooling with liquid helium at -270 °C. They are contained inside a vacumm-insulated helmet called a dewar, which is filled with liquid. SQUIDS are placed in fixed positions inside the helmet dewar in the helium coolant, and a subject's head is placed inside the helmet dewar for MEG measurements. The helmet dewar must be sized to satisfy opposing constraints. Clearly, it must be large enough to fit most or all of the heads in the population that will be studied. However, the helmet must also be small enough to keep most of the SQUID sensors within range of the tiny cerebral fields that they are to measure. Conventional whole-head MEG systems are designed to accommodate more than 90% of adult heads. However adult systems are not well suited for measuring brain function in pre-school chidren whose heads have a radius several cm smaller than adults. The KIT-Macquarie Brain Research Laboratory at Macquarie University uses a MEG system custom sized to fit the heads of pre-school children. This child system has 64 first-order axial gradiometers with a 50 mm baseline [2] and is contained inside a magnetically-shielded room (MSR) together with a conventional adult-sized MEG system [3,4]. There are three main advantages of the customized helmet dewar for studying children. First, the smaller radius of the sensor configuration brings the SQUID sensors into range of the neuromagnetic signals of children's heads. Second, the smaller helmet allows full insertion of a child's head into the dewar. Full insertion is prevented in adult dewar helmets because of the smaller crown to shoulder distance in children. These two factors are fundamental in recording brain activity using MEG because neuromagnetic signals attenuate rapidly with distance. Third, the customized child helmet aids in the symmetric positioning of the head and limits the freedom of movement of the child's head within the dewar. When used with a protocol that aligns the requirements of data collection with the motivational and behavioral capacities of children, these features significantly facilitate setup, positioning, and measurement of MEG signals. Video LinkThe video component of this article can be found at http://www.jove.com/video/1693/ ProtocolThese guidelines describe equipment and procedures for measuring cognitive brain function in preschoolers using magnetoencephalography (MEG). First, we discuss general guidelines and issues that must be considered when carrying experimental tests of cognitive function in children. Second, we describe a protocol developed to align the requirements of MEG data collection with the mot...

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Measurement of brain function in pre-school children using a custom sized whole-head MEG sensor array

Cited by 75 publications

References 19 publications

Face processing in the brains of pre-school aged children measured with MEG

Face processing in the brains of pre-school aged children measured with MEG

Practical Aspects of Running Developmental Studies in the MEG

Measurement Of Neuromagnetic Brain Function In Pre-school Children With Custom Sized MEG

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