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Shoko Watanabe

Publications and source records attributed to Shoko Watanabe.

10 recordsLinked to original sources
PubMed2004

Interaction between auditory and visual stimulus relating to the vowel sounds in the auditory cortex in humans: a magnetoencephalographic study.

We investigated the interaction between auditory and visual stimulus relating to the vowel sounds in the auditory cortex in humans, using magnetoencephalography. We compared the difference in the main component, M100 generated in the auditory cortex, in terms of peak latency, amplitude, dipole location and moment, following the vowel sound_/a/_between two conditions: (1) showing a face with closed mouth; and (2) showing the same face with mouth movement appearing to pronounce/a/using an apparent motion method. We found no significant difference in the M100 component between the two conditions within or between the right and left hemispheres. These findings indicated that the vowel sound perception in the auditory cortex, at least in the primary processing stage, was not affected by viewing mouth movement.

Acoustic Stimulation↗
PubMed2004

Magnetoencephalographic study of occipitotemporal activity elicited by viewing mouth movements.

OBJECTIVE: We studied the temporal and spatial characteristics of neural responses elicited by viewing mouth movements using magnetoencephalography. METHODS: We focused on differences in responses to mouth opening and closing movements by apparent motion, using an averting eyes condition as a control. RESULTS: A large clear MEG component, 1 M (mean peak latency of approximately 160 ms), was elicited by both mouth movements. We modeled the neural sources using a brain electric source analysis (BESA) method and placed the sources around: (1) the occipitotemporal border at human MT/V5, (2) the primary visual cortex (V1), and (3) fusiform gyrus. The calculated activity of Source (1) was large whereas the activity of the others was small or negligible. Source (1), as calculated separately for mouth closing and opening movements and eye movement, showed no significant different amplitude and locations. We did not find any activity in the superior temporal sulcus (STS). CONCLUSIONS: Our results indicate that human MT/V5 is active in the perception of both mouth and eye motions. Viewing mouth and eye movements elicits no significant differences in MT/V5 activity, indicating that the perception of movement of facial parts is probably processed in the same manner. SIGNIFICANCE: Characteristic activities in the human MT/V5 elicited by viewing mouth movement were clarified by MEG.

Adult↗
PubMed2004

Cholesterol metabolism in rat is affected by protocatechuic acid.

The effects of protocatechuic acid on serum cholesterol and gene expression related to cholesterol metabolism in rats were investigated. Rats were fed a cholesterol-free diet with or without 5 g protocatechuic acid/kg diet for 4 wk. There were no significant differences in body weight and food intake among groups through the experimental period. The liver weight in the protocatechuic acid group was significantly lower than that in the control group. The serum total cholesterol, high-density lipoprotein (HDL)-cholesterol and very low-density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low-density lipoprotein (LDL)-cholesterol concentrations in the protocatechuic acid group were significantly lower than those in the control group through the feeding period. The hepatic cholesterol concentration in the protocatechuic acid group was significantly higher than in the control group at the end of the 4-wk feeding period. The relative hepatic LDL receptor, apo B, apo E, lecithin-cholesterol acyltransferase (LCAT) and hepatic triglyceride lipase (HTGL) mRNA levels in the protocatechuic acid group were significantly higher than those in the control group. The results of this study suggest the possibility that the increase in the hepatic LDL receptor, apo E, LCAT and HTGL guessed by these mRNAs increase in the protocatechuic acid group lowers the serum total cholesterol level.

Animals↗
PubMed2004

Human brain processing and central mechanisms of pain as observed by electro- and magneto-encephalography.

We review the recent progress of electroencephalography (EEG) and magnetoencephalography (MEG) to elucidate pain perception mechanisms in humans, since EEG and MEG have an excellent temporal resolution in order of msec. MEG is more useful to detect activated areas following painful stimulation, because the spatial resolution of EEG is not very high. For recording activities following Adelta fiber stimulation relating to the first pain, painful CO2 laser stimulation is now widely used, but our new method, epidermal stimulation (ES), is also very useful. The primary small activity was recorded from the primary somatosensory cortex (SI), probably in area 1, in the hemisphere contralateral to the stimulation. Then, secondary somatosensory cortex (SII) and insula were activated with the second activity in SI. These 3 regions were activated in parallel with almost the same time period. This is a very characteristic finding in pain perception. Then, the cingulate cortex and medial temporal area (MT) around the amygdala and hippocampus were activated. In the hemisphere ipsilateral to the stimulation as well, the above regions were activated, except for SI. Therefore, we speculated that SI plays a main role in localization of the stimulus point, the SII and insula are important sites for pain perception, and the cingulate and MT are mainly responsible for cognitive or emotional aspects of pain perception. For recording activities following C fiber stimulation relating to the second pain, we recently developed a new method, that is, applying weaker CO2 laser stimuli to tiny areas of the skin. MEG findings following C fiber stimulation were also similar to those following Adelta fiber stimulation. However, the effects of sleep and attention on MEG following C fiber stimulation was much larger than that following Adelta fiber stimulation. This finding may suggest greater effects of cognitive or emotional functions on second pain than the first pain.

Brain↗
PubMed2003

Cerebral responses following stimulation of unmyelinated C-fibers in humans: electro- and magneto-encephalographic study.

There are two kinds of pain, a sharp pain ascending through Adelta fibers (first pain) and a second burning pain ascending though C fibers (second pain). By using a novel method, the application of a low intensity CO(2) laser beam to a tiny area of skin using a very thin aluminum plate with numerous tiny holes as a spatial filter, we succeeded in selectively stimulating unmyelinated C fibers of the skin in humans, and could record consistent and clear brain responses using electroencephalography (EEG) and magnetoencephalography (MEG). The conduction velocity (CV) of the C fibers of the peripheral nerve and spinal cord, probably spinothalamic tract (STT), is approximately 1-4 m/s, which is significantly slower than that of Adelta (approximately 10-15 m/s) and Abeta fibers (approximately 50-70 m/s). This method should be very useful for clinical application. Following C fiber stimulation, primary and secondary somatosensory cortices (SI and SII) are simultaneously activated in the cerebral hemisphere contralateral to the stimulation, and then, SII in the hemisphere ipsilateral to the stimulation is activated. These early responses are easily detected by MEG. Then, probably limbic systems such as insula and cingulate cortex are activated, and those activities reflected in EEG components. Investigations of the cortical processing in pain perception including both first and second pain should provide a better understanding of pain perception and, therefore, contribute to pain relief in clinical medicine.

Animals↗
PubMed2003

Brain responses for the subconscious recognition of faces.

We investigated the event-related responses following subthreshold and suprathreshold stimulation with facial and non-facial figures using magnetoencephalography (MEG) and EEG recordings to clarify the physiological nature of subconscious perception. Event-related magnetic fields and potentials were recorded from the right hemisphere in eight healthy subjects. Three types of stimulus, i.e., facial image (Face), letters of the alphabet (Letters) and random patterns of dots (Dots), with different presentation periods, subthreshold (16 ms), intermediate (32 ms) and suprathreshold (48 ms) were visually presented in a random order. A psychological discrimination task using the same stimuli was also employed. Clear MEG and EEG responses were recorded for all the stimuli, but the amplitude of the responses was largest for Face and smallest for Dots even in the subthreshold stimulation. The equivalent current dipoles (ECDs) for Face were located around the fusiform gyrus, although the correlation coefficients for ECDs were low under subthreshold and intermediate conditions. The ECDs for Letters and Dots were not estimated with reliable correlation coefficients. The results from the psychological task correlated with the dominancy of face recognition. Face perception was processed differently in the subthreshold condition as well as suprathreshold condition. The subconscious recognition of face might be processed around the fusiform gyrus.

Adult↗
PubMed2003

Sensory perception during sleep in humans: a magnetoencephalograhic study.

We reported the changes of brain responses during sleep following auditory, visual, somatosensory and painful somatosensory stimulation by using magnetoencephalography (MEG). Surprisingly, very large changes were found under all conditions, although the changes in each were not the same. However, there are some common findings. Short-latency components, reflecting the primary cortical activities generated in the primary sensory cortex for each stimulus kind, show no significant change, or are slightly prolonged in latency and decreased in amplitude. These findings indicate that the neuronal activities in the primary sensory cortex are not affected or are only slightly inhibited during sleep. By contrast, middle- and long-latency components, probably reflecting secondary activities, are much affected during sleep. Since the dipole location is changed (auditory stimulation), unchanged (somatosensory stimulation) or vague (visual stimulation) between the state of being awake and asleep, different regions responsible for such changes of activity may be one explanation, although the activated regions are very close to each other. The enhancement of activities probably indicates two possibilities, an increase in the activity of excitatory systems during sleep, or a decrease in the activity of some inhibitory systems, which are active in the awake state. We have no evidence to support either, but we prefer the latter, since it is difficult to consider why neuronal activities would be increased during sleep.

Adult↗
PubMed2003

Mouse germ cell-less as an essential component for nuclear integrity.

A mouse homologue of the Drosophila melanogaster germ cell-less (mgcl-1) gene is expressed ubiquitously, and its gene product is localized to the nuclear envelope based on its binding to LAP2 beta (lamina-associated polypeptide 2 beta). To elucidate the role of mgcl-1, we analyzed two mutant mouse lines that lacked mgcl-1 gene expression. Abnormal nuclear morphologies that were probably due to impaired nuclear envelope integrity were observed in the liver, exocrine pancreas, and testis. In particular, functional abnormalities were observed in testis in which the highest expression of mgcl-1 was detected. Fertility was significantly impaired in mgcl-1-null male mice, probably as a result of severe morphological abnormalities in the sperm. Electron microscopic observations showed insufficient chromatin condensation and abnormal acrosome structures in mgcl-1-null sperm. In addition, the expression patterns of transition proteins and protamines, both of which are essential for chromatin remodeling during spermatogenesis, were aberrant. Considering that the first abnormality during the process of spermatogenesis was abnormal nuclear envelope structure in spermatocytes, the mgcl-1 gene product appears to be essential for appropriate nuclear-lamina organization, which in turn is essential for normal sperm morphogenesis and chromatin remodeling.

Animals↗
PubMed2002

Gaze direction affects face perception in humans.

We recorded event-related potentials (ERP) in response to images of faces with a straight gaze (straight eyes) and eyes averted (averted eyes). Peak latencies of ERP components showed no significant change between straight eyes and averted eyes, but amplitude for averted eyes, particularly when averted to the right, was significantly larger than that for straight eyes at the lateral temporal electrode of the right hemisphere. Single-unit recordings in monkeys and neuroimaging studies in humans have revealed activity in the lateral temporal region, mainly the superior temporal sulcus, and a clinical study demonstrated the importance of the right hemisphere when viewing gaze direction. This is the first systematic neurophysiological report to confirm these findings using ERP.

Adult↗