Limits...
Magnetoencephalography detection of high-frequency oscillations in the developing brain.

Leiken K, Xiang J, Zhang F, Shi J, Tang L, Liu H, Wang X - Front Hum Neurosci (2014)

Bottom Line: The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals.Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG.MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA.

ABSTRACT
Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG) methods. Twenty healthy children were studied with a high-sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (>1000 Hz) in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI) revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

No MeSH data available.


Magnetic source images showing the sources of brain activation elicited by finger stimulation in a representative subject. Note that, the somatosensory cortex generates signals in a wide frequency range. Very high-frequency signals (1000–2000 and 2000–3000 Hz) may be also generated by the deep brain area, which is possibly from the thalamus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4264504&req=5

Figure 5: Magnetic source images showing the sources of brain activation elicited by finger stimulation in a representative subject. Note that, the somatosensory cortex generates signals in a wide frequency range. Very high-frequency signals (1000–2000 and 2000–3000 Hz) may be also generated by the deep brain area, which is possibly from the thalamus.

Mentions: Magnetic source imaging revealed MEG signals at 1–20 and 20–500 Hz from the somatosensory cortex in 17 subjects (17/20, 85%), MEG signals at 500–1000 Hz from the somatosensory cortex in 6 subjects (6/20, 30%), and MEG signals at 1000–2000 and 2000–3000 Hz from the somatosensory in 18 subjects (18/20, 90%). MEG signals within the range of 1000–2000 and 2000–3000 Hz were also localized to the deep brain area, likely the thalamus, in 18 subjects (18/20, 90%) and 14 subjects (14/20, 70%), respectively. The result of statistical group analysis revealed that the source strength of MEG signals at 1–20 Hz was significantly stronger than that of MEG signals at 2000–3000 Hz in the primary somatosensory cortex (SI) for both left and right stimulation (p < 0.001). The result of statistical group analysis did not reveal significantly different SI source coordinates for each of the frequency bands (1–20, 20–500, 500–1000, 1000–2000, and 2000–3000 Hz). However, the source coordinates of the DA in 1000–2000 Hz was significantly different from that of the SI activation (p < 0.001). Figure 5 shows the source locations of MEG signals in all the frequency ranges for a healthy subject. The sources of very high-frequency signals around the occipital regions were localized to the posterior regions, which were outside of the brain and were determined to be muscle artifacts. Figure 6 shows an example of one of these muscle artifacts in the posterior regions.


Magnetoencephalography detection of high-frequency oscillations in the developing brain.

Leiken K, Xiang J, Zhang F, Shi J, Tang L, Liu H, Wang X - Front Hum Neurosci (2014)

Magnetic source images showing the sources of brain activation elicited by finger stimulation in a representative subject. Note that, the somatosensory cortex generates signals in a wide frequency range. Very high-frequency signals (1000–2000 and 2000–3000 Hz) may be also generated by the deep brain area, which is possibly from the thalamus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4264504&req=5

Figure 5: Magnetic source images showing the sources of brain activation elicited by finger stimulation in a representative subject. Note that, the somatosensory cortex generates signals in a wide frequency range. Very high-frequency signals (1000–2000 and 2000–3000 Hz) may be also generated by the deep brain area, which is possibly from the thalamus.
Mentions: Magnetic source imaging revealed MEG signals at 1–20 and 20–500 Hz from the somatosensory cortex in 17 subjects (17/20, 85%), MEG signals at 500–1000 Hz from the somatosensory cortex in 6 subjects (6/20, 30%), and MEG signals at 1000–2000 and 2000–3000 Hz from the somatosensory in 18 subjects (18/20, 90%). MEG signals within the range of 1000–2000 and 2000–3000 Hz were also localized to the deep brain area, likely the thalamus, in 18 subjects (18/20, 90%) and 14 subjects (14/20, 70%), respectively. The result of statistical group analysis revealed that the source strength of MEG signals at 1–20 Hz was significantly stronger than that of MEG signals at 2000–3000 Hz in the primary somatosensory cortex (SI) for both left and right stimulation (p < 0.001). The result of statistical group analysis did not reveal significantly different SI source coordinates for each of the frequency bands (1–20, 20–500, 500–1000, 1000–2000, and 2000–3000 Hz). However, the source coordinates of the DA in 1000–2000 Hz was significantly different from that of the SI activation (p < 0.001). Figure 5 shows the source locations of MEG signals in all the frequency ranges for a healthy subject. The sources of very high-frequency signals around the occipital regions were localized to the posterior regions, which were outside of the brain and were determined to be muscle artifacts. Figure 6 shows an example of one of these muscle artifacts in the posterior regions.

Bottom Line: The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals.Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG.MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Magnetoencephalography (MEG) Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA ; Department of Neurology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA.

ABSTRACT
Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG) methods. Twenty healthy children were studied with a high-sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (>1000 Hz) in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI) revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

No MeSH data available.