Frontal midline theta rhythm (Fm theta) is a distinct theta activity of EEG in the frontal midline area that appears during concentrated performance of mental tasks in normal subjects and reflects focused attentional processing. To tomographically visualize the source current density distributions of Fm theta, we recorded Fm theta by using a 64-channel whole-head MEG system from four healthy subjects, and applied a new analysis method, synthetic aperture magnetometry (SAM), an adaptive beam forming method. Fm theta was observed in the MEG signals over the bilateral frontal regions. SAM analysis showed bilateral medial prefrontal cortices, including anterior cingulate cortex, as the source of Fm theta. This result suggests that focused attention is mainly related to medial prefrontal cortex.

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This study quantified the effects of head rotation on pharyngeal swallowing in healthy subjects. Videofluoroscopic and oropharyngeal manometric examinations of pharyngeal swallowing were performed on seven volunteers with the head in neutral and rotated positions. Videofluoroscopic study revealed that head rotation swallow causes the bolus to lateralize away from the direction of head rotation. Pharyngeal manometric study indicated that the pharyngeal peak pressures toward the side of head rotation were significantly increased, whereas the pharyngeal pressures opposite the side of head rotation were not affected. Head rotation swallow produced a significant fall in upper esophageal sphincter (UES) resting pressure and a delay in UES closing. We concluded that the head rotation swallow in normal subjects not only alters the bolus pathway, but also has a useful effect on both pharyngeal clearance and UES dynamics.

Auditory hallucinations (AH), the perception of sounds and voices in the absence of external stimuli, remain a serious problem for a large subgroup of patients with schizophrenia. Functional imaging of brain activity associated with AH is difficult, since the target event is involuntary and its timing cannot be predicted. Prior efforts to image the patterns of cortical activity during AH have yielded conflicting results. In this study, MEG was used to directly image the brain electrophysiological events associated with AH in schizophrenia. We observed an increase in theta rhythm, as sporadic bursts, in the left superior temporal area during the AH states, whereas there was steady theta band activity in the resting state. The present finding suggests strong association of the left superior temporal cortex with the experience of AH in this patient. This is consistent with the hypothesis that AH arises from areas of auditory cortex subserving receptive language processing.