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.

To investigate the role of the prefrontal cortex (PFC) in processing multimodal communicative ostensive signals in infants, we measured cerebral hemodynamic responses by using near-infrared spectroscopy (NIRS) during the social interactive play "peek-a-boo", in which both visual (direct gaze) and auditory (infant-directed speech) stimuli were presented. The infants (mean age, around 7 months) sat on their mother's lap, equipped with an NIRS head cap, and looked at a partner's face during "peek-a-boo". An eye-tracking system simultaneously monitored the infants' visual fixation patterns. The results indicate that, when the partner presented a direct gaze, rather than an averted gaze, toward an infant during social play, the infant fixated on the partner's eye region for a longer duration. Furthermore, hemodynamic activity increased more prominently dorsomedial prefrontal cortex (mPFC) in response to social play with a partner's direct gaze compared to an averted gaze. In contrast, hemodynamic activity increased in the right dorsolateral prefrontal cortex (R-lPFC) regardless of a partner's eye gaze direction. These results indicate that a partner's direct gaze shifts an infant's attention to the partner's eyes for interactive communication, and specifically activates the mPFC. The differences in hemodynamic responses between the mPFC and R-lPFC suggest functional differentiation within the PFC, and a specific role of the mPFC in the perception of face-to-face communication, especially in mutual gaze, which is essential for social interaction.

These results indicate that compression at MTrPs is effective to treat acute low back pain compared with compression at non-MTrPs and superficial massage. For this article, a commentary is available at the Wiley Online Library.

Ota et al. PFC Neurofeedback Improves Hand Dexterity performance improvement rates in the motor rehabilitation task. The results suggest that the aPFC might shape activity in the somatosensory motor-related areas to improve hand dexterity. These findings further suggest that the motor imagery training using neurofeedback signals from the aPFC might be useful to patients with motor disability.