JNL: Brain Cortical Mapping by Simultaneous Recording of Functional Near Infrared Spectroscopy and Electroencephalograms from the Whole Brain
Brain Topogr.
2009 Aug 25. [Epub ahead of print]
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.
System Emotional Science, Graduate School of Medicine and Pharmaceutical
Sciences, University of Toyama, Sugitani 2630, Toyama, 930-0194, Japan.
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.
PMID: 19705276 [PubMed - as supplied by publisher]
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