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Brain cortical mapping by simultaneous recording of functional near infrared spectroscopy and electroencephalograms from the whole brain during right median nerve stimulation.

Takeuchi M, Hori E, Takamoto K, Tran AH, Satoru K, Ishikawa A, Ono T, Endo S, Nishijo H - Brain Topogr (2009)

Bottom Line: Comparison of these two sets of data indicated that the distance between the dipoles of P22 and NIRS channels with maximum hemodynamic responses was less than 10 mm, and that the two topographical maps of hemodynamic responses and current source density of P22 were significantly correlated.This suggests that GLM analysis with onset delay could reveal the temporal ordering of neural activation in the hierarchical somatosensory pathway, consistent with the neurophysiological data.The present results suggest that simultaneous NIRS and EEG recording is useful for correlating hemodynamic responses to neural activity.

View Article: PubMed Central - PubMed

Affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama, Japan.

ABSTRACT
To investigate relationships between hemodynamic responses and neural activities in the somatosensory cortices, hemodynamic responses by near infrared spectroscopy (NIRS) and electroencephalograms (EEGs) were recorded simultaneously while subjects received electrical stimulation in the right median nerve. The statistical significance of the hemodynamic responses was evaluated by a general linear model (GLM) with the boxcar design matrix convoluted with Gaussian function. The resulting NIRS and EEGs data were stereotaxically superimposed on the reconstructed brain of each subject. The NIRS data indicated that changes in oxy-hemoglobin concentration increased at the contralateral primary somatosensory (SI) area; responses then spread to the more posterior and ipsilateral somatosensory areas. The EEG data indicated that positive somatosensory evoked potentials peaking at 22 ms latency (P22) were recorded from the contralateral SI area. Comparison of these two sets of data indicated that the distance between the dipoles of P22 and NIRS channels with maximum hemodynamic responses was less than 10 mm, and that the two topographical maps of hemodynamic responses and current source density of P22 were significantly correlated. Furthermore, when onset of the boxcar function was delayed 5-15 s (onset delay), hemodynamic responses in the bilateral parietal association cortices posterior to the SI were more strongly correlated to electrical stimulation. This suggests that GLM analysis with onset delay could reveal the temporal ordering of neural activation in the hierarchical somatosensory pathway, consistent with the neurophysiological data. The present results suggest that simultaneous NIRS and EEG recording is useful for correlating hemodynamic responses to neural activity.

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Group-averaged SEP data when 10-Hz stimulation was applied. A SEPs recorded from the 32 electrodes. GFP, global field power. Other descriptions as for Fig. 2. B EEG data (SEPs) shown in (A) were subjected to CSD transformation. The data were shown using two different calibrations since the CSD peaks in the ipsilateral parietal cortex were so small that magnified calibration was used. C Comparison of the amplitudes and peak latencies of P22. There were no significant differences in these parameters among the three stimulus frequencies
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Fig6: Group-averaged SEP data when 10-Hz stimulation was applied. A SEPs recorded from the 32 electrodes. GFP, global field power. Other descriptions as for Fig. 2. B EEG data (SEPs) shown in (A) were subjected to CSD transformation. The data were shown using two different calibrations since the CSD peaks in the ipsilateral parietal cortex were so small that magnified calibration was used. C Comparison of the amplitudes and peak latencies of P22. There were no significant differences in these parameters among the three stimulus frequencies

Mentions: The above data (Figs. 2, 3, 4, 5) indicated examples of the data derived from a single subject in 10-Hz electrical stimulation. The data from each subject were analyzed individually using the realistic head models so that the original 3-D coordinates were preserved. Furthermore we analyzed the group-averaged EEG data. Figure 6A showed such group-averaged SEPs. The results were essentially similar to those in Fig. 2b; positivity was observed around the contralateral somatosensory cortex at latency of 22 and 47 ms. Figure 6B shows the CSD maps at the latency of 22 (a), 47 (b), and 100 (c) ms indicated in Fig. 6A. CSD increased in the contralateral (left) parietal area not only at the latency of P22 (Ba; 22 ms), but also at the latency of P47 (Bb: 47 ms), and finally disappeared at 100 ms latency (Bc; 100 ms). Consistent with the data in the single subject (Fig. 4), CSD also increased in the ipsilateral parietal area at P47 (Bb; 47 ms) in the magnified calibration, although its intensity was much lower than that in the contralateral parietal area. Figure 6C indicates reliability of SEP waveforms across the three stimulation frequencies. Statistical analyses by one-way repeated measures ANOVA indicated that there were no significant differences in the amplitudes of P22 [F(2,24) = 2.257, P > 0.05], nor in the latencies of P22 [F(2,24) = 3.083, P > 0.05], This indicated that the SEPs were stable regardless of stimulation frequencies.Fig. 6


Brain cortical mapping by simultaneous recording of functional near infrared spectroscopy and electroencephalograms from the whole brain during right median nerve stimulation.

Takeuchi M, Hori E, Takamoto K, Tran AH, Satoru K, Ishikawa A, Ono T, Endo S, Nishijo H - Brain Topogr (2009)

Group-averaged SEP data when 10-Hz stimulation was applied. A SEPs recorded from the 32 electrodes. GFP, global field power. Other descriptions as for Fig. 2. B EEG data (SEPs) shown in (A) were subjected to CSD transformation. The data were shown using two different calibrations since the CSD peaks in the ipsilateral parietal cortex were so small that magnified calibration was used. C Comparison of the amplitudes and peak latencies of P22. There were no significant differences in these parameters among the three stimulus frequencies
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2749167&req=5

Fig6: Group-averaged SEP data when 10-Hz stimulation was applied. A SEPs recorded from the 32 electrodes. GFP, global field power. Other descriptions as for Fig. 2. B EEG data (SEPs) shown in (A) were subjected to CSD transformation. The data were shown using two different calibrations since the CSD peaks in the ipsilateral parietal cortex were so small that magnified calibration was used. C Comparison of the amplitudes and peak latencies of P22. There were no significant differences in these parameters among the three stimulus frequencies
Mentions: The above data (Figs. 2, 3, 4, 5) indicated examples of the data derived from a single subject in 10-Hz electrical stimulation. The data from each subject were analyzed individually using the realistic head models so that the original 3-D coordinates were preserved. Furthermore we analyzed the group-averaged EEG data. Figure 6A showed such group-averaged SEPs. The results were essentially similar to those in Fig. 2b; positivity was observed around the contralateral somatosensory cortex at latency of 22 and 47 ms. Figure 6B shows the CSD maps at the latency of 22 (a), 47 (b), and 100 (c) ms indicated in Fig. 6A. CSD increased in the contralateral (left) parietal area not only at the latency of P22 (Ba; 22 ms), but also at the latency of P47 (Bb: 47 ms), and finally disappeared at 100 ms latency (Bc; 100 ms). Consistent with the data in the single subject (Fig. 4), CSD also increased in the ipsilateral parietal area at P47 (Bb; 47 ms) in the magnified calibration, although its intensity was much lower than that in the contralateral parietal area. Figure 6C indicates reliability of SEP waveforms across the three stimulation frequencies. Statistical analyses by one-way repeated measures ANOVA indicated that there were no significant differences in the amplitudes of P22 [F(2,24) = 2.257, P > 0.05], nor in the latencies of P22 [F(2,24) = 3.083, P > 0.05], This indicated that the SEPs were stable regardless of stimulation frequencies.Fig. 6

Bottom Line: Comparison of these two sets of data indicated that the distance between the dipoles of P22 and NIRS channels with maximum hemodynamic responses was less than 10 mm, and that the two topographical maps of hemodynamic responses and current source density of P22 were significantly correlated.This suggests that GLM analysis with onset delay could reveal the temporal ordering of neural activation in the hierarchical somatosensory pathway, consistent with the neurophysiological data.The present results suggest that simultaneous NIRS and EEG recording is useful for correlating hemodynamic responses to neural activity.

View Article: PubMed Central - PubMed

Affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama, Japan.

ABSTRACT
To investigate relationships between hemodynamic responses and neural activities in the somatosensory cortices, hemodynamic responses by near infrared spectroscopy (NIRS) and electroencephalograms (EEGs) were recorded simultaneously while subjects received electrical stimulation in the right median nerve. The statistical significance of the hemodynamic responses was evaluated by a general linear model (GLM) with the boxcar design matrix convoluted with Gaussian function. The resulting NIRS and EEGs data were stereotaxically superimposed on the reconstructed brain of each subject. The NIRS data indicated that changes in oxy-hemoglobin concentration increased at the contralateral primary somatosensory (SI) area; responses then spread to the more posterior and ipsilateral somatosensory areas. The EEG data indicated that positive somatosensory evoked potentials peaking at 22 ms latency (P22) were recorded from the contralateral SI area. Comparison of these two sets of data indicated that the distance between the dipoles of P22 and NIRS channels with maximum hemodynamic responses was less than 10 mm, and that the two topographical maps of hemodynamic responses and current source density of P22 were significantly correlated. Furthermore, when onset of the boxcar function was delayed 5-15 s (onset delay), hemodynamic responses in the bilateral parietal association cortices posterior to the SI were more strongly correlated to electrical stimulation. This suggests that GLM analysis with onset delay could reveal the temporal ordering of neural activation in the hierarchical somatosensory pathway, consistent with the neurophysiological data. The present results suggest that simultaneous NIRS and EEG recording is useful for correlating hemodynamic responses to neural activity.

Show MeSH
Related in: MedlinePlus